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John Dalton
He was and English chemist who developed a popular idea that spread worldwide. .He decided that elements particles that combine in simplesways. His theories were 1)All matter is made of atoms that can be combined. 2)Atoms of the same element are exactly alike. 3)Atoms of different elements are different. 4)Atoms of two or more element can be combined to form new substances. He publised an article for the Manchester Literary and Philosophical Society in 1803. -
Sir Williams Crookes
He was responsible for the identification and isolation of the element thallium in 1861. He was interested in too many areas of science to be able to focus in on one specific area, and between 1854 and 1900 he studied extensively in the fields of chemistry, physics, mathematics, and even economics. Crookes’ main contribution to the advancement of the atomic theory, however, is his identification of many properties of cathode rays; Crookes discovered that these rays move in a straight line, caus -
Neils Bhor
Proposed that electrons orbit around the nucleus. He stated that each electron has a fixed amount of energy that the electrons orbit within energy levels forming rings around the nucleus. The farther you go away from the nucleus the amount of energy increases by absorbing or release energy. An electron can move between energy levels. He discoved this theory the 7 of October, 1885 -
JJ Thomson
In the late 19th century scientist who stated atoms were not simple solid spheres. He discovered electrons. Electrons: Located outside the nucleus and have a negative charge. That's what causes the needle in the compass point north. In 1897 he discovered the electron. -
Albert Einstein
HE discovered the famous equation E = mc^2. In 1905 Albert Einstein formulates Special Theory of Relativity. He established law of mass- energy equivalence; through his famous formula E=mc². It means (energy equals mass times the velocity of light squared), became the foundation stone in the development of atomic energy. Einstein’s relativity theory revolutionized scientific thought with new conceptions of time, space, mass, motion, and gravitation. -
Ernest Rutherford
Developed a more complete understanding of the structure of atoms. After his experiment he concluded that atoms were made mostly of space. Another thing he claimed was that the atom had a small dent positively charged center that repelled the positively charged bullets. He called the center of the atom the Nucleus: Positively charged center of atom. All of the atoms positively charged particles were in the nucleus and the negatively charge particles were outside the nucleus. -
Erwin Schrodinger
A powerful model of the atom was developed by Erwin in 1926. The Schrodinger model assumes that the electron is a wave and tries to describe the regions in space, or orbitals, where electrons are most likely to be found. Instead of trying to tell us where the electron is at any time, the Schrodinger model describes the probability that an electron can be found in a given region of space at a given time. This model no longer tells us where the electron is; it only tells us where it might be. -
James Chadwick
In 1932, Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons. James predicted the atom would have a neutron. He established the numbers of protons in an atom determines that atomic number.He also discovered the fourth subatomic particle, the neutron. He also thought that neutrons would become a major weapon in the fight against cancer. He wrote the final draft of the MAUD Report, which inspired the U.S. government to begin serious atom
