CHEM 1211 Chapter Notes - Chapter 2: Calcium Chloride, Formula Unit, Weighted Arithmetic Mean
9 Nov 2017
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Nucleus: positively charged center of atom containing nearly all the mass of the atom, about 1/1,000 the size of an atom, consists of 2 types of particles, proton, pos. charged subatomic particle, neutron, electronically neutral subatomic particle. In a neutral nuclide: units used to express the relative masses of. Amu: atomic mass number atoms and subatomic particles based on natural abundances average of all the isotopes put together: underneath each element in the periodic table, carbon was chosen as standard of measurement. 6 protons + 6 neutrons = 12 amu. J. j. thomson discovered electron: rutherford said electrons orbited the nucleus, bohr developed this theory even more , anything w/ atomic number > 83 is radioactive. Me(cid:374)deleev"s periodi(cid:272) ta(cid:271)le: ordered elements by increasing atomic mass. Protons were not yet discovered: arranged elements in columns based on similar chemical and physical properties left space for elements not yet discovered.
