1. question

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.