CHEM 1151 Lecture Notes - Lecture 9: Relative Atomic Mass, Unified Atomic Mass Unit, Sodium Chloride
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Electronegativity: ability of an atom in a bond to pull e- to itself. The most electronegative element: upper right side of the pt (f). The least electronegative element: bottom left side of the pt (cs or fr) Predicting the type of bond formed: difference in electronegativity values, covalent: 0 - 0. 4, polar covalent: 0. 5 1. 4. Ionic: 1. 5 and above: metal/nonmetal: ionic, 2 nonmetals: covalent. Formula weight or molecular weight the weight, in amu, of the compound. If a subscript appears in the formula, multiply the previous atom/polyatomic ion by this factor. Nacl = 23. 0 + 35. 5 = 58. 5 amu. Caso4 = 40. 1 + 32. 1 + 4(16. 0) = 136. 2 amu (nh4)2s = 2(14. 0) + 8(1. 0) + 32. 1 = 68. 1 amu. C6h12o6 = 6(12. 0) + 12(1. 0) + 6(16. 0) = 180. 0 amu. A(cid:448)ogadro"s (cid:374)u(cid:373)(cid:271)er = 6. (cid:1004)(cid:1006)(cid:1006) e (cid:1006)(cid:1007) thi(cid:374)gs.
