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John Dalton
John Dalton (1766-1844) was an english chemist who is known for his contribution with the atom and it's structure. He first developed his theory in 1803. His theory is: Dalton's Atomic Theory
1) All matter is made of atoms. Atoms are indivisible and indestructible. 2) All atoms of a given element are identical in mass and properties 3) Compounds are formed by a combination of two or more different kinds of atoms. 4) A chemical reaction is a rearrangement of atoms. -
J.J. Thomson
J.J. Thomson was an english physicist who is known for discovering the electron in 1897, a major discovery for the atom and it's structure. He discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged, hense discovering the electron. -
Ernest Rutherford
Ernest Rutherford was a new zealand born physicist known for his gold foil experiment in which he demonstrated that the atom has a tiny, heavy nucleus. -
Niels Bohr
Niels Bohr was a danish physicist known for his theory that he proposed for the hydrogen atom based on quantum theory that energy is transferred only in certain defined quantities. Electrons should move around the nucleus but only in prescribed orbits. -
James Chadwick
James Chadwick was an english psycisist known for discovering the neutron. Chadwick bombarded beryllium atoms with alpha particles. An unknown radiation was produced. Chadwick interpreted this radiation as being composed of particles with a neutral electrical charge and the approximate mass of a proton. This particle became known as the neutron.
