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John Dalton (1766-1844)
profmokeur.com/chemistry/history_of_the_atom.htm' >John Dalton (1766-1844) was such a brilliant youth that he became an English shool teacher when barely 12 years old. "Daltons theory" All matter is made of atoms. Atoms are indivisible and indestructible.
All atoms of a given element are identical in mass and properties.
Compounds are formed by a combination of two or more different kinds of atoms.
A chemical reaction is a rearrangement of atoms.
Atoms can be neither created or destroyed. -
J.J Thomson (1856–1940)
J.J Thomsons atomic theory model was like a chocolate chip cookie with the postitive charges being the chocolate chips and the negative part is the rest of the cookie. Thomson changed the view on the atom when he found the electron. -
Ernest Rutherford(1871–1937)
<a href='http://http://profmokeur.com/chemistry/history_of_the_atom.htm' > Based on an experiment he had performed - with totally unexpected results - he realized that the atom must have almost all of its mass concentrated at its center, in a nucleus, with the vast majority of the atom consisting chiefly of empty space. They shot alpha particals at a thin layer of gold to study the deflection of angles. He descovered that most the atoms wait is at its nucleus. -
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James Chadwick 1891-1974
href='http://profmokeur.com/chemistry/history_of_the_atom.htm' >In 1932, James Chadwick identified the neutron. Chadwick was now able to explain the existence of isotopes through his discovery of the neutron. Isotopes of the same element have the same number of protons and electrons but differ in the number of neutrons found in their nucleus.