Democritus- stated the idea of atoms. He believed that atoms made up matter, and that they could not be divided no further. These atoms were all composed of the same primary matter with the only differences between them being their size, shape and weight. The differences in these characteristics explained the differences in the properties of the matter around us. John Dalton- In came up with the atomic theory in 1803.1.All matter was composed of small indivisible particles called atoms2.Atoms of the same element are alike in weight and other properties, atoms of different emelements are different in weight and other properties.3. Compounds are formed by atoms that seperate. 4. A chemical reaction is a rearrangement of atoms. Dalton's theory also helped further the concept of atomic weights.
J.J. Thompson- He is givin credit for the discovery of the electron. He founded the electron while doing the cathode ray experiment. He found that cathode rays could be deflected by an electric field Showed that cathode "rays" were actually particles. He believed that matter is electrically neutral and electrons are much lighter than atoms.
Ernest Rutherford- He was known as the father of physics. He discovered the concept of radio active half life. He won the Nobel Prize in 1908. His main discovery happened during his famous gold foil experiment. He is given credit to be the first to split an atom. He is given credit for the proton. He belivied that all the mass was in the center of the atom.
Neils Bohr-1913---Bohr made numerous contributions to our understanding of atomic structure and quantum mechanics. He stated that the electrons moved around the nucleus in successively large orbits. He also presented the Bohr atomic model which stated that atoms absorb or emit radiation only when the electrons abruptly jump between allowed, or stationary, states.
Marie Curie- She studied Uranium and Thorium and called there spontaneous decay Radioactivity. She and her husband were awarded the Nobel prize in 1903. She eventually won it on her own in 1911. She became the first person to receive the award twice. She is credited of radioactivity of an element.
Wener Heisenberg- a German Scientist that is known as a contrubuter to quantom mechanics. He is best known for the uncertainty principle of the quantum theory. The uncertainty principle states by precise inequalities that certain pairs of physical properties, such as position and momentom cannot be simultaneously known to arbitrarily high precision. He was awarded the nobel prize in 1932.
Enrico Fermi- He is known for his work on the first nuclear reactor. He was given the Nobel prize in 1932 for his work on induced radioactivity. He is known as the father of the atom bomb.
Monday, October 25, 2010
Essay Question #1 Jonathan Slonaker Chemistry 1st Period
John Dalton- The English teacher, chemist, and physicist John Dalton, b. Sept. 6, 1766, d. July 27, 1844, is best known for developing the concept of atoms into a scientific theory that has become a foundation of modern chemistry. Dalton's atomic theory provided a model from which definite predictions of atoms could be made. each atom has a characteristic mass and that atoms of elements are unchanged in chemical processes.
J.J. Thomson- Sir Joseph John Thomson, b. Dec. 18, 1856, d. Aug. 30, 1940, is universally recognized as the British scientist who discovered and identified the electron. Thomson demonstrated that cathode rays were actually units of electrical current made up of negatively charged particles of subatomic size. He came up with a theory that negative particles were embeded into a positive mass. He won the Nobel Prize for physics; in 1908 he was knighted.
Ernest Rutherford-Sir Ernest Rutherford, b. near Nelson, New Zealand, Aug. 30, 1871, d. Oct. 19, 1937 formed modern-day views concerning the nature of matter. Rutherford made his greatest discovery; the structure of the atom. A very small, tightly packed, charged nucleus sprinkled with opposite charges in the mostly empty surrounding void.
Werner Heisenberg-German theoretical physicist Werner Karl Heisenberg, b. Dec. 5, 1901, d. Feb. 1, 1976, was one of the leading scientists of the 20th century. He did important work in nuclear and particle physics, but his most significant contribution was to the development of quantum mechanics. He is best known for his uncertainty principle, which restricts the accuracy with which some properties of atoms and particles--such as position and linear momentum--can be determined simultaneously.
Erwin Schrodinger-The Austrian theoretical physicist Erwin Schrodinger, b. Aug. 12, 1887, d. Jan. 4, 1961, was founder of the wave equation. His studies of the application and statistical interpretation of wave mechanics, the mathematical character of the new statistics, and the relationship of these statistics to statistical thermodynamics earned him fame in the scientific community. He also worked on problems of general relativity and cosmology and on a unified field theory. Late in his life Schrodinger studied the foundations of physics and their implications for philosophy.
Wolfgang Pauli-The Austrian theoretical physicist Wolfgang Ernst Pauli, b. Apr. 25, 1900, d. Dec. 15, 1958, was one of the founders of modern physics. He is most famous for his "Pauli exclusion principle," which states that no two electrons in an atom can have the same four quantum numbers.
James Chadwick-The English physicist James Chadwick, b. Oct. 20, 1891, d. July 24, 1974, is known for his discovery of the neutron. His experiments on the bombardment of certain light elements with alpha particles led to the discovery of the neutron.
Gilbert Lewis-The American chemist Gilbert Newton Lewis, b. West Newton, Mass., Oct. 25, 1875, d. Mar. 23, 1946, contributed to the study of thermodynamics, atomic structure, and bonding, as well as to the theory of acids and bases and the teaching of thermodynamics. Lewis's work in thermodynamics led him to confirm H. Walther Nernst's third law of thermodynamics. His atomic model, known as the Lewis-Langmuir octet, and his distinction between ionic and covalent bonds marked great progress in understanding chemical bonding. His acid-base concept, which asserted that a base donates an electron pair and an acid accepts the pair in covalent bonding, superseded the Bronsted-Lowry theory.
Linus Pauling-The American physical chemist Linus Carl Pauling, b. Portland, Oregon, Feb. 28, 1901, has made extensive contributions to structural chemistry and molecular biology.In the early 1950s he proposed the alpha helix as the basic structure of proteins and narrowly missed discovering the double-helix structure of DNA.
John Dalton- The English teacher, chemist, and physicist John Dalton, b. Sept. 6, 1766, d. July 27, 1844, is best known for developing the concept of atoms into a scientific theory that has become a foundation of modern chemistry. Dalton's atomic theory provided a model from which definite predictions of atoms could be made. each atom has a characteristic mass and that atoms of elements are unchanged in chemical processes.
J.J. Thomson- Sir Joseph John Thomson, b. Dec. 18, 1856, d. Aug. 30, 1940, is universally recognized as the British scientist who discovered and identified the electron. Thomson demonstrated that cathode rays were actually units of electrical current made up of negatively charged particles of subatomic size. He came up with a theory that negative particles were embeded into a positive mass. He won the Nobel Prize for physics; in 1908 he was knighted.
Ernest Rutherford-Sir Ernest Rutherford, b. near Nelson, New Zealand, Aug. 30, 1871, d. Oct. 19, 1937 formed modern-day views concerning the nature of matter. Rutherford made his greatest discovery; the structure of the atom. A very small, tightly packed, charged nucleus sprinkled with opposite charges in the mostly empty surrounding void.
Werner Heisenberg-German theoretical physicist Werner Karl Heisenberg, b. Dec. 5, 1901, d. Feb. 1, 1976, was one of the leading scientists of the 20th century. He did important work in nuclear and particle physics, but his most significant contribution was to the development of quantum mechanics. He is best known for his uncertainty principle, which restricts the accuracy with which some properties of atoms and particles--such as position and linear momentum--can be determined simultaneously.
Erwin Schrodinger-The Austrian theoretical physicist Erwin Schrodinger, b. Aug. 12, 1887, d. Jan. 4, 1961, was founder of the wave equation. His studies of the application and statistical interpretation of wave mechanics, the mathematical character of the new statistics, and the relationship of these statistics to statistical thermodynamics earned him fame in the scientific community. He also worked on problems of general relativity and cosmology and on a unified field theory. Late in his life Schrodinger studied the foundations of physics and their implications for philosophy.
Wolfgang Pauli-The Austrian theoretical physicist Wolfgang Ernst Pauli, b. Apr. 25, 1900, d. Dec. 15, 1958, was one of the founders of modern physics. He is most famous for his "Pauli exclusion principle," which states that no two electrons in an atom can have the same four quantum numbers.
James Chadwick-The English physicist James Chadwick, b. Oct. 20, 1891, d. July 24, 1974, is known for his discovery of the neutron. His experiments on the bombardment of certain light elements with alpha particles led to the discovery of the neutron.
Gilbert Lewis-The American chemist Gilbert Newton Lewis, b. West Newton, Mass., Oct. 25, 1875, d. Mar. 23, 1946, contributed to the study of thermodynamics, atomic structure, and bonding, as well as to the theory of acids and bases and the teaching of thermodynamics. Lewis's work in thermodynamics led him to confirm H. Walther Nernst's third law of thermodynamics. His atomic model, known as the Lewis-Langmuir octet, and his distinction between ionic and covalent bonds marked great progress in understanding chemical bonding. His acid-base concept, which asserted that a base donates an electron pair and an acid accepts the pair in covalent bonding, superseded the Bronsted-Lowry theory.
Linus Pauling-The American physical chemist Linus Carl Pauling, b. Portland, Oregon, Feb. 28, 1901, has made extensive contributions to structural chemistry and molecular biology.In the early 1950s he proposed the alpha helix as the basic structure of proteins and narrowly missed discovering the double-helix structure of DNA.
Dalton Levy
Democritus - Formulated an atomic theories for cosmos. during the 19th century and helped understand the atomic structure.
Lavoisier- He stated the first version of the law of conservation of mass and he also recognized and named oxygen and many more. He also helped construct the metric system.
John Dalton- He is best known for his pioneering work in the development of modern atomic theory, and his research into color blindness. his beliefs are sometimes referred to as Daltonism, in his honor.
J.J. Thomson- He is credited for the discovery of the electron and of isotopes, and the invention of the mass spectrometer. Thomson was awarded the 1906 Nobel Prize in Physics for the discovery of the electron and for his work on the conduction of electricity in gases.
Ernest Rutherford-In early work he discovered the concept of radioactive half life, proved that radioactivity involved the transmutation of one chemical element to another, and also differentiated and named alpha and beta radiation.
Marie Curie-creation of a theory of radioactivity, techniques for isolating radioactive isotopes, and the discovery of two new elements, polonium and radium. Under her direction, the world's first studies were conducted into the treatment of neoplasms using radioactive isotopes
Enrico Fermi- work on the development of the first nuclear reactor and for his contributions to the development of quantum theory, nuclear and particle physics, and statistical mechanics.
Atomic theory history
Examine the history of the development of the atom. We have already discussed the major players in the development of the atom. Pick out at least 8 major players who helped aid in the development of the concept of the atom. Explain each experiment in a concise explanation. Then explain how each one aided in the development of the next or how their concept assisted in the further development of the current quantum model of the atom.
Democritus - (460 B.C.) that everything is composed of "atoms", which are physically, but not geometrically, indivisible. He tested how many times could you physically break something down till it was impossible to break down any more. The Democritean atom is an inert solid that interacts with other atoms mechanically.
Lavoisier- He was intrigued by Democritus’ findings and began looking with more detail at the atom. He is credited with the defining elements. He made the first example of a heliostat, which was used to capture sunlight
John Dalton- He introduced the atomic theory. (All matter is composed of atoms) (Atoms of the same element are alike in weight and other properties, atoms of
different elements are different in weight and other properties.)(Compounds are formed fromed by the union of separation of definite number of atoms.)(Atoms do not divide in chemical reactions; only whole atoms unite with other other
atoms.)
J.J. Thomson- Looked more into Daltons’ theory, and cathode rays. He found that these rays are streams of particles much smaller than atoms, they are tiny pieces of atoms. The rays are made up of electrons.
Ernest Rutherford- He researched radioactivity with his gold foil experiment. He shot alpha particles at a sheet of gold and realized that some alpha particles bounced back and others did not, and he thought there must be some kind of small particle or nucleus .
Marie Curie- She studied Uranium and Thorium and called there spontaneous decay Radioactivity.
Neils Bohr- Came up with a structure for atoms. Devolped a structure of atoms that makes up the periodic table of elements.
Enrico Fermi- He made the first controlled chain reaction by releasing energy into the atoms nucleus.
Examine the history of the development of the atom. We have already discussed the major players in the development of the atom. Pick out at least 8 major players who helped aid in the development of the concept of the atom. Explain each experiment in a concise explanation. Then explain how each one aided in the development of the next or how their concept assisted in the further development of the current quantum model of the atom.
Democritus- Democritus stated that matter was composed of small particles called atoms. "The only differences between them is their size, shape and weight."
John Dalton- he made the 5 laws about atoms listed below. they helped the concept of atomic wieghts.
"1. Matter is made up of indivisible atoms.
2. All atoms of an element are identical.
3. Atoms are neither created nor destroyed.
4. Atoms of different elements have different weights and chemical properties.
5. Atoms of different elements combine in simple whole numbers to form compounds."
Mendeleev- he Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law. he also helped arrange the periodic table.
J.J. Thompson-
Found that cathode rays could be deflected by an electric field Showed that cathode "rays" were actually particles
Raising Pudding Model -
Matter is electrically neutral and electrons are much lighter than atoms.
Conclusion: There must be positively charged
particles which also must carry the mass of the
atom. Dalton's model is now incorrect because
atoms are divisible.
Rutherford- Studied absorption of radioactivity.
"* Alpha radiation - positive charge - absorbed by a few hundredths of a cm or metal foil
*
Beta radiation - negative charge - could pass through 100x as much foil before it was absorbed
*
Gamma rays - no charge - could penetrate several cm of lead
Rutherford was also able to estimate the charge of an atom by studying the deflection of alpha particles. He found that the positive charge on the atom was approximately half of the atomic weight."
Bohr- helped to understand atomic structure and quantum mechanics and came up with the Bohr model of the atom.
Mosely- arranged the periodic table based on atomic number. this helped later scientists.
Chadwick- "discovered neutron with radioactivity -
"* Proved that neutrons, neutral particles in the nucleus that made up approximately
half the mass of an atom, did exist."
"Atomic Rules
* The number of protons in the nucleus of an atom is equal to the atomic number (Z).
* In a neutral atom, the number of electrons is equal to the number of protons.
* The mass number (M) of an atom is equal to the sum of the number of
protons and neutrons in the nucleus.
* The number of neutrons is equal to the difference between the mass number (M)
and the atomic number (Z)."
sources - wikipedia (quoted text)
Democritus- Democritus stated that matter was composed of small particles called atoms. "The only differences between them is their size, shape and weight."
John Dalton- he made the 5 laws about atoms listed below. they helped the concept of atomic wieghts.
"1. Matter is made up of indivisible atoms.
2. All atoms of an element are identical.
3. Atoms are neither created nor destroyed.
4. Atoms of different elements have different weights and chemical properties.
5. Atoms of different elements combine in simple whole numbers to form compounds."
Mendeleev- he Arranged elements into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law. he also helped arrange the periodic table.
J.J. Thompson-
Found that cathode rays could be deflected by an electric field Showed that cathode "rays" were actually particles
Raising Pudding Model -
Matter is electrically neutral and electrons are much lighter than atoms.
Conclusion: There must be positively charged
particles which also must carry the mass of the
atom. Dalton's model is now incorrect because
atoms are divisible.
Rutherford- Studied absorption of radioactivity.
"* Alpha radiation - positive charge - absorbed by a few hundredths of a cm or metal foil
*
Beta radiation - negative charge - could pass through 100x as much foil before it was absorbed
*
Gamma rays - no charge - could penetrate several cm of lead
Rutherford was also able to estimate the charge of an atom by studying the deflection of alpha particles. He found that the positive charge on the atom was approximately half of the atomic weight."
Bohr- helped to understand atomic structure and quantum mechanics and came up with the Bohr model of the atom.
Mosely- arranged the periodic table based on atomic number. this helped later scientists.
Chadwick- "discovered neutron with radioactivity -
"* Proved that neutrons, neutral particles in the nucleus that made up approximately
half the mass of an atom, did exist."
"Atomic Rules
* The number of protons in the nucleus of an atom is equal to the atomic number (Z).
* In a neutral atom, the number of electrons is equal to the number of protons.
* The mass number (M) of an atom is equal to the sum of the number of
protons and neutrons in the nucleus.
* The number of neutrons is equal to the difference between the mass number (M)
and the atomic number (Z)."
sources - wikipedia (quoted text)
Justin Walton Question 1A
-Democritus- He said that everything is composed of indivisible atoms. He said that there is an infinite number of kinds of atoms, and this is why there are differences in the physical matter in our world.
John Dalton- He is credited with developing the first atomic theory that said all matter is made up of atoms, and that all atoms of the same element are identical. The atoms of different elements are different. He also said that atoms can't be created nor destroyed. His work helped to arrange atoms by atomic weight like they are in the current periodic table.
Mendeleev- He discovered that when elements were arranged in order of increasing mass, there was a pattern in elements that were vertically alligned. He discovered this by using cards with element names and various properties listed on them. He would arrange them according to certain characteristics, and on one of these arrangements he noticed a pattern.
J.J. Thomson- Thomson made a groundbreaking discovery in the development of the atomic model when he discovered electrons. He discovered this through his cathode ray experiment. He found that the rays could be deflected by an electric field, and used the deflection to determine the particle's mass. He discovered a particle 2000 times lighter than hydrogen and determined that it was negatively charged.
Rutherford- Rutherford performed the gold foil experiment. He hypothesized that atoms were composed of both positive and negative charges. He then shot alpha particles at a very thin sheet of gold foil and noticed that while most passed straight through, a small amount were deflected. He determined that they were hitting a large positive mass which later became known as the nucleus. He is credited with discovering the proton.
Niels Bohr- He composed the Bohr model of the atom. This described atoms as having small positively charged nucleus' and electrons that orbit in perfect circles, similar to the Solar System. Bohr made many contributions in the development of the atomic bomb.
Moseley-He devised a periodic table sat up by atomic number rather than atomic mass. He also determined a way for the number to be mathematically figured rather than just represent the place the element is on the table. This allowed scientist to understand physical makeup of atoms and develop a better model for the atom.
Chadwick- He is credited with the discovery of the neutron. he discovered this by colliding berrylium atoms which released massive neutral particles. His discovery made it possible for later scientists to construct new elements in the lab.
"Wikipedia," "answers.com"
John Dalton- He is credited with developing the first atomic theory that said all matter is made up of atoms, and that all atoms of the same element are identical. The atoms of different elements are different. He also said that atoms can't be created nor destroyed. His work helped to arrange atoms by atomic weight like they are in the current periodic table.
Mendeleev- He discovered that when elements were arranged in order of increasing mass, there was a pattern in elements that were vertically alligned. He discovered this by using cards with element names and various properties listed on them. He would arrange them according to certain characteristics, and on one of these arrangements he noticed a pattern.
J.J. Thomson- Thomson made a groundbreaking discovery in the development of the atomic model when he discovered electrons. He discovered this through his cathode ray experiment. He found that the rays could be deflected by an electric field, and used the deflection to determine the particle's mass. He discovered a particle 2000 times lighter than hydrogen and determined that it was negatively charged.
Rutherford- Rutherford performed the gold foil experiment. He hypothesized that atoms were composed of both positive and negative charges. He then shot alpha particles at a very thin sheet of gold foil and noticed that while most passed straight through, a small amount were deflected. He determined that they were hitting a large positive mass which later became known as the nucleus. He is credited with discovering the proton.
Niels Bohr- He composed the Bohr model of the atom. This described atoms as having small positively charged nucleus' and electrons that orbit in perfect circles, similar to the Solar System. Bohr made many contributions in the development of the atomic bomb.
Moseley-He devised a periodic table sat up by atomic number rather than atomic mass. He also determined a way for the number to be mathematically figured rather than just represent the place the element is on the table. This allowed scientist to understand physical makeup of atoms and develop a better model for the atom.
Chadwick- He is credited with the discovery of the neutron. he discovered this by colliding berrylium atoms which released massive neutral particles. His discovery made it possible for later scientists to construct new elements in the lab.
"Wikipedia," "answers.com"
Test Question 1A
-Examine the history of the development of the atom. We have already discussed the major players in the development of the atom. Pick out at least 8 major players who helped aid in the development of the concept of the atom. Explain each experiment in a concise explanation. Then explain how each one aided in the development of the next or how their concept assisted in the further development of the current quantum model of the atom.
1) The first atomic theory was made by Democritus in 460 B.C. He asked this question: If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further? Democritus thought that it ended at some point, a smallest possible bit of matter. He called these basic matter particles, atoms. These atoms were all composed of the same primary matter with the only differences between them being their size, shape and weight. The differences in these characteristics explained the differences in the properties of the matter around us.
2) Couloumb (1780's), France - formulated the Coulomb's law, which states that that the force between two electrical charges is proportional to the product of the charges and inversely proportional to the square of the distance between them, one of the main forces involved in atomic reactions.
3) John Dalton helped to explain the laws of chemical reactivity; He performed experiments with various chemicals that showed that matter, indeed, seem to consist of elementary lumpy particles (atoms). Although he did not know about their structure, he knew that the evidence pointed to something fundamental. Dalton's theory also helped further the concept of atomic weights. By assuming that nature would be a simple as possible, Dalton assumed that the elements preferred to combine in one to one ratios, and was therefore able to tabulate a set of relative weights.
Dalton's theory can be summarized as follows:
-Matter is composed of small particles called atoms.
-All atoms of an element are identical, but are different from those of any other element.
-During chemical reactions, atoms are neither created nor destroyed, but are simply rearranged.
-Atoms always combine in whole number multiples of each other.
4) In 1897, the English physicist J.J. Thomson discovered the electron and proposed a model for the structure of the atom. Thomson knew that electrons had a negative charge and thought that matter must have a positive charge.
5) Robert Millikan (1908), USA - found out the electric charge of the electron. He determined the unit charge of the electron in 1909 with his oil drop experiment at the University of Chicago. Thus allowing for the calculation of the mass of the electron and the positively charged atoms. e = 1.60 x 10^-19 coulombs
6) Ernest Rutherford-1909-1911---British physicist, who became a Nobel laureate for his pioneering work in nuclear physics and for his theory of the structure of the atom. He used the results of his gold-foil experiment to state that all the mass of an atom were in a small positively-charged ball at the center of the atom.
7) Neils Bohr-1913---Bohr made numerous contributions to our understanding of atomic structure and quantum mechanics. He stated that the electrons moved around the nucleus in successively large orbits. He also presented the Bohr atomic model which stated that atoms absorb or emit radiation only when the electrons abruptly jump between allowed, or stationary, states.
Bohr’s Rules:
-Electrons can orbit only at certain allowed distances from the nucleus.
-Atoms radiate energy when an electron jumps from a higher-energy orbit to a lower-energy orbit. Also, an atom absorbs energy when an electron gets boosted from a low-energy orbit to a high-energy orbit.
8) In 1931 Chadwick discovered the neutrally-charged neutron. He found it to measure slightly heavier than the proton with a mass of 1840 electrons and with no charge (neutral). The proton-neutron together, received the name, "nucleon.”
1) The first atomic theory was made by Democritus in 460 B.C. He asked this question: If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further? Democritus thought that it ended at some point, a smallest possible bit of matter. He called these basic matter particles, atoms. These atoms were all composed of the same primary matter with the only differences between them being their size, shape and weight. The differences in these characteristics explained the differences in the properties of the matter around us.
2) Couloumb (1780's), France - formulated the Coulomb's law, which states that that the force between two electrical charges is proportional to the product of the charges and inversely proportional to the square of the distance between them, one of the main forces involved in atomic reactions.
3) John Dalton helped to explain the laws of chemical reactivity; He performed experiments with various chemicals that showed that matter, indeed, seem to consist of elementary lumpy particles (atoms). Although he did not know about their structure, he knew that the evidence pointed to something fundamental. Dalton's theory also helped further the concept of atomic weights. By assuming that nature would be a simple as possible, Dalton assumed that the elements preferred to combine in one to one ratios, and was therefore able to tabulate a set of relative weights.
Dalton's theory can be summarized as follows:
-Matter is composed of small particles called atoms.
-All atoms of an element are identical, but are different from those of any other element.
-During chemical reactions, atoms are neither created nor destroyed, but are simply rearranged.
-Atoms always combine in whole number multiples of each other.
4) In 1897, the English physicist J.J. Thomson discovered the electron and proposed a model for the structure of the atom. Thomson knew that electrons had a negative charge and thought that matter must have a positive charge.
5) Robert Millikan (1908), USA - found out the electric charge of the electron. He determined the unit charge of the electron in 1909 with his oil drop experiment at the University of Chicago. Thus allowing for the calculation of the mass of the electron and the positively charged atoms. e = 1.60 x 10^-19 coulombs
6) Ernest Rutherford-1909-1911---British physicist, who became a Nobel laureate for his pioneering work in nuclear physics and for his theory of the structure of the atom. He used the results of his gold-foil experiment to state that all the mass of an atom were in a small positively-charged ball at the center of the atom.
7) Neils Bohr-1913---Bohr made numerous contributions to our understanding of atomic structure and quantum mechanics. He stated that the electrons moved around the nucleus in successively large orbits. He also presented the Bohr atomic model which stated that atoms absorb or emit radiation only when the electrons abruptly jump between allowed, or stationary, states.
Bohr’s Rules:
-Electrons can orbit only at certain allowed distances from the nucleus.
-Atoms radiate energy when an electron jumps from a higher-energy orbit to a lower-energy orbit. Also, an atom absorbs energy when an electron gets boosted from a low-energy orbit to a high-energy orbit.
8) In 1931 Chadwick discovered the neutrally-charged neutron. He found it to measure slightly heavier than the proton with a mass of 1840 electrons and with no charge (neutral). The proton-neutron together, received the name, "nucleon.”
Sunday, October 24, 2010
Question #1, Sarah Lloyd, 2nd Period.
Important People in the Development of the Atom
Democritus - A Greek philosopher who came up with the atomic theory of the universe:
- Everything is composed of atoms, which are physically indivisible.
- Between atoms lies empty space.
- Atoms are indestructible.
- Always in motion.
- Infinite number number of atoms which differ in shape and size.
Lavoisier - a French chemist who was the founder of modern chemistry. Lavoisier clarified the concept of an element as a simple substance that can't be broken down. He made the theory that the formation of chemical compounds is from elements.
Dalton - British chemist who developed the atomic theory.
- The atoms of a given element are different from those of any other element; the atoms of different elements can be distinguished from one another by their respective relative atomic weights.
- All atoms of an element are identical.
- Atoms of one element can combine with atoms of other elements to form chemical compounds.
- Atoms cannot be created, divided into small pieces, nor destroyed in the chemical process.
- Elements are made of tiny particles called atoms.
The Curies - Pierre Curie and Marie Curie stated that radioactive materials cause atoms to break down spontaneously which releases radiation in energy form and subatomic particle form. Their experiments used techniques for isolating radioactive isotopes which led to the discovery of two new elements, polonium and radium. Marie Curie began the first studies of conducting the treatment of cancers using radiative isotopes.
JJ Thompson - discovered the electron. He discovered electrons by his explorations on the properties of cathode rays. He found that the rays could be deflected by an electric field. He compared the deflection of a beam of cathode rays by electric and magnetic fields and was able to measure the particle's mass. This showed that cathode rays were matter, but he found that the particles were lighter and then concluded that the rays were composed of light nevatively charged particles which were electrons.
Ernest Rutherford - discovered that positively charged nucleus was orbited by electrons. He found this out by his Rutherford model. Rutherford also found the existence of neutrons, which compensated for the repelling effect of the positive charges of protons by causing a nuclear force. This kept the nuclei from breaking apart.
Niels Bohr - found that atoms have a positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus, like the solar system, but with electrostatic forces that provided attraction. The Rutherford model helped him and he also made the Bohr model. The Bohr model is a complex idea of valence shell atoms.
Chadwick - discovered that neutron because of the lack of its electric charge. He learned that neutrons do not need to overcome any Coulomb barrier and penetrated and split the nuclei of elements. His discovery helped make it possible to make uranium in the laboratory.
Each scientist provided more and more insight on how the atom is made up and how it works in our everyday lives. As time went on, the scientist had more technology to test all theories and proved each one. Bohr and Rutherford helped each other by making models of the atom which eventually led to the quantum model.
Thursday, October 21, 2010
Question #1- Todd Thornal 2nd Period
Democritus- Democritus stated that matter was composed of small particles called "atoms" that could be divided no further. These atoms were all composed of the same primary matter with the only differences between them being their size, shape and weight. The differences in these characteristics explained the differences in the properties of the matter around us.
John Dalton- credited with developing the first coherent atomic theory that states that matter is composed of small particles called atoms, all atoms of an element are identical, but are different from those of any other element, atoms are neither created nor destroyed, but are simply rearranged, and atoms always combine in whole number multiples of each other. Dalton's theory also helped further the concept of atomic weights.
Mendeleev- Mendeleev arranged the elements in order of increasing atomic weight and he discovered that there existed a periodicity of the elemental properties. He used this to create a table in which that elements with similar properties were vertically aligned with each other.
J.J. Thomson- performed an experiment with a cathode ray and was able to determine the mass to charge ratio of these particles by varying the potential on the plates. He found negatively charged particles and said that they were subatomic particles that were part of every atom and that the atom must also contain some positive charge. Thomson proposed that an atom was composed of a positive charge and was credited with discovering protons
Rutherford- Said that the atom was composed of positive and negative charges and made a experiment that allowed alpha particles to be shot at a very thin piece of gold foil while monitered the trajectory. He observed some particles were deflected to a great degree. This force could only be caused by a large concentration of positive charges within the atom. This charge was located at the center of the atom and later became known as the nucleus. Rutherford is credited for discovering the electon and is known for his famous Gold Foil experiment.
Bohr- made fundamental contributions to understanding atomic structure and quantum mechanics and came up with the Bohr model of the atom that depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus.
Mosely- Set up the periodic table based on atomic number instead of Mendeleev's version with atomic weight. Mosely's version of the periodic table helped scientist later make more discoveries of the atom.
Chadawick- proved the existence of neutrons by using particles emitted through radioactivity to discover the neutrally charged partical.
Through many outstanding discoveries these scientist have been able to come up with many different models of the atom and have been able to find out much more information about the atom.
Sources:
Wednesday, October 20, 2010
Emmy Dickson
Question #1- EMMY DICKSON, CHEMISTRY 1st period
- 12 Major Scientists chosen to discuss:
Democritus, Lavosier, John Dalton, Demetri Mendeleev, J.J. Thompson, Ernest
Rutherford, Marie Curie, Mosely, Neils Bohr, Schrodienger, James Chadwick, Enrico
Fermi.
370 B.C.- Democritus composed the theory of "atoms", which are physically, but not geometrically, indivisible. He also stated that between atoms lies empty space; that atoms are indestructible and constantly in motion; that there are an infinite number of atoms, and kinds of atoms, which differ in shape, and size. Using analogies from our sense experiences, he gave a picture or an image of an atom that distinguished them from each other by their shape, their size, and the arrangement of their parts.
1700- Lavoisier became curious after the findings of Democritus and later defined what we know as "elements" today; substances that have definite chemical properties. Lavoisier built a Solar Furnace. This is the first example of a heliostat, which is a device used to concentrate sunlight. Many of his discoveries required a great deal of heat to burn off impurities from or cause reactions in the samples he was working with.
1800- John Dalton proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass.
Atomic Theory:
1. All matter is composed of atoms
2. Atoms of the same element are alike in weight and other properties, atoms of
different emelements are different in weight and other properties.
3. Compounds are formed fromed by the union of separation of definitie number of atoms.
4. Atoms do not divide in chemical reactions; only whole atoms unite with other other
atoms.
1869- After Lavoisier discovered elements, Demetri Mendeleev arranged them into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law.
1898- After Dalton stated the atomic theory, J.J. Thompson wanted to know more. He was investigating a long-standing puzzle known as "cathode rays." His experiments prompted him to make a bold proposal: these mysterious rays are streams of particles much smaller than atoms, they are in fact minuscule pieces of atoms. The rays are made up of electrons: very small, negatively charged particles that are indeed fundamental parts of every atom.
1898- While Rutherford was performing his various experiments in the field of radioactivity, bombarding nitrogen gas with alpha particles (alpha particles are a type of radiation), he noticed that one of the experimental results was a surge of hydrogen. He correctly deduced that the hydrogen atoms must have come from within the nitrogen atoms themselves, which would mean that there was something within all of these atoms which was divisible, the amount of which would determine what element the atom represented. He is known for the famous Gold Foil Experiment.
1898- After Rutherford studied the elements uranium and thorium, Marie Curie took these elements and called their spontaneous decay process "radioactivity". She and her husband Pierre also discovered the radioactive elements polonium and radium. She started taking elements and figuring out more information.
1914- After Mendeleev constructed the periodic table based on atomic weight, Henry G. Mosely used his work to reorganize the periodic table based upon atomic number instead. Using x-ray tubes, determined the charges on the nuclei of most atoms. He wrote"The atomic number of an element is equal to the number of protons in the nucleus".
1922- After all of this talk about atoms, Neils Bohr was the first to come up with an estimated structure of an atom. He developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons.
1930- Once J.J. Thompson had come up with the discovery of the electron, Schrodienger Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom.
1932- James Chadwick heard of a new method of detecting particles emitted by radioactive elements developed by Irene Joliot-Curie, one of Marie Curie's daughters, and her husband, Frederic. He used this new technique and discovered that there were different particles in the nucleus which were neutrally charged.
1942- After the majority of the basic knowledge needed to know about the atom, Enrico Fermi conducted the first controlled chain reaction releasing energy from the atoms nucleus.
3 ATOMIC MODELS:
Bohr, Thompson (plum mudding), Rutherford
each of these were revised by a later scientist who had gained more knowledge over the years and helped lead to the discovery of todays quantum model of the atomic structure.
Each of these scientists helped aid in each discovery to the next. Because of all these experiments, today's society now has a clear understanding of the atoms, the particles it makes up, and how atoms react with one another.
Source Helped:
http://www.cartage.org.lb/en/themes/sciences/physics/atomicphysics/atomicstructure/atomictimeline/atomictimeline.htm
- 12 Major Scientists chosen to discuss:
Democritus, Lavosier, John Dalton, Demetri Mendeleev, J.J. Thompson, Ernest
Rutherford, Marie Curie, Mosely, Neils Bohr, Schrodienger, James Chadwick, Enrico
Fermi.
370 B.C.- Democritus composed the theory of "atoms", which are physically, but not geometrically, indivisible. He also stated that between atoms lies empty space; that atoms are indestructible and constantly in motion; that there are an infinite number of atoms, and kinds of atoms, which differ in shape, and size. Using analogies from our sense experiences, he gave a picture or an image of an atom that distinguished them from each other by their shape, their size, and the arrangement of their parts.
1700- Lavoisier became curious after the findings of Democritus and later defined what we know as "elements" today; substances that have definite chemical properties. Lavoisier built a Solar Furnace. This is the first example of a heliostat, which is a device used to concentrate sunlight. Many of his discoveries required a great deal of heat to burn off impurities from or cause reactions in the samples he was working with.
1800- John Dalton proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass.
Atomic Theory:
1. All matter is composed of atoms
2. Atoms of the same element are alike in weight and other properties, atoms of
different emelements are different in weight and other properties.
3. Compounds are formed fromed by the union of separation of definitie number of atoms.
4. Atoms do not divide in chemical reactions; only whole atoms unite with other other
atoms.
1869- After Lavoisier discovered elements, Demetri Mendeleev arranged them into 7 groups with similar properties. He discovered that the properties of elements "were periodic functions of the their atomic weights". This became known as the Periodic Law.
1898- After Dalton stated the atomic theory, J.J. Thompson wanted to know more. He was investigating a long-standing puzzle known as "cathode rays." His experiments prompted him to make a bold proposal: these mysterious rays are streams of particles much smaller than atoms, they are in fact minuscule pieces of atoms. The rays are made up of electrons: very small, negatively charged particles that are indeed fundamental parts of every atom.
1898- While Rutherford was performing his various experiments in the field of radioactivity, bombarding nitrogen gas with alpha particles (alpha particles are a type of radiation), he noticed that one of the experimental results was a surge of hydrogen. He correctly deduced that the hydrogen atoms must have come from within the nitrogen atoms themselves, which would mean that there was something within all of these atoms which was divisible, the amount of which would determine what element the atom represented. He is known for the famous Gold Foil Experiment.
1898- After Rutherford studied the elements uranium and thorium, Marie Curie took these elements and called their spontaneous decay process "radioactivity". She and her husband Pierre also discovered the radioactive elements polonium and radium. She started taking elements and figuring out more information.
1914- After Mendeleev constructed the periodic table based on atomic weight, Henry G. Mosely used his work to reorganize the periodic table based upon atomic number instead. Using x-ray tubes, determined the charges on the nuclei of most atoms. He wrote"The atomic number of an element is equal to the number of protons in the nucleus".
1922- After all of this talk about atoms, Neils Bohr was the first to come up with an estimated structure of an atom. He developed an explanation of atomic structure that underlies regularities of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons.
1930- Once J.J. Thompson had come up with the discovery of the electron, Schrodienger Viewed electrons as continuous clouds and introduced "wave mechanics" as a mathematical model of the atom.
1932- James Chadwick heard of a new method of detecting particles emitted by radioactive elements developed by Irene Joliot-Curie, one of Marie Curie's daughters, and her husband, Frederic. He used this new technique and discovered that there were different particles in the nucleus which were neutrally charged.
1942- After the majority of the basic knowledge needed to know about the atom, Enrico Fermi conducted the first controlled chain reaction releasing energy from the atoms nucleus.
3 ATOMIC MODELS:
Bohr, Thompson (plum mudding), Rutherford
each of these were revised by a later scientist who had gained more knowledge over the years and helped lead to the discovery of todays quantum model of the atomic structure.
Each of these scientists helped aid in each discovery to the next. Because of all these experiments, today's society now has a clear understanding of the atoms, the particles it makes up, and how atoms react with one another.
Source Helped:
http://www.cartage.org.lb/en/themes/sciences/physics/atomicphysics/atomicstructure/atomictimeline/atomictimeline.htm
Monday, October 18, 2010
1A
Examine the history of the development of the atom. We have already discussed the
major players in the development of the atom. Pick out at least 8 major players who
helped aid in the development of the concept of the atom. Then explain each
experiment in a concise explanation. Then explain how each one aided in the
development of the next or how their concept assisted in the further development of the current quantum model of the atom.
major players in the development of the atom. Pick out at least 8 major players who
helped aid in the development of the concept of the atom. Then explain each
experiment in a concise explanation. Then explain how each one aided in the
development of the next or how their concept assisted in the further development of the current quantum model of the atom.
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