CHM 2045 Lecture Notes - Lecture 4: Georgia State Route 31, Unified Atomic Mass Unit, Hydrogen Chloride
28 Feb 2017
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When adding- cant have digits past decimal place in sum unless all number being added had decimals: remember to round up to a whole number for a decimal number above . 5. When multiplying/dividing- product must have the same number of sigfigs as number with lowest amount of sigfigs. Dalton(1808)- atomic model with indivisible atoms: laws of multiple proportions and definite compositions, conservation of mass in chemical reactions. Curie(1898)- discovered (cid:862)radioa(cid:272)tivity(cid:863): e(cid:373)issio(cid:374) of su(cid:271)ato(cid:373)i(cid:272) parti(cid:272)les(divisible atoms) Thompson(1898)- (cid:862)(cid:272)athode rays(cid:863): (cid:374)egatively (cid:272)harged ele(cid:272)tro(cid:374)s: mass/charge ratio of electrons (cathode rays typically=(-1. 76x10-8 c/g), simple plum pudding model with negative and positive charges. Milken(1909)- oil drop x-ray bombardment experiment: absolute charge of electron=(-1. 60x10-19 c, mass of electrons-(-1. 60x10-19 c)/(1. 76x10-8 c/g)=9. 10x10-28 g. Rutherford(1910)- gold foil experiment: positively charged nucleus surrounded by electrons. Chadwick(1935)- mass of atoms> mass of protons and electrons only: neutrally charged neutrons with similar mass as protons. X: mass number-protons and neutrons z:atomic mass- protons.
