CHM 2353 Lecture Notes - Lecture 4: Trigonal Planar Molecular Geometry, Trigonal Pyramidal Molecular Geometry, Triangular Bipyramid
4 Nov 2017
School
Department
Course
Professor
Document Summary
Covalent e- shared by atoms in compound. Metallic sea of e- delocalized throughout cationic lattice. Ionic e- transfer: then electrostatic attration b/w ions. Electronegativity & the chemical bond: the pauling scale. Electronegativity diff for a-b reports on bond covalency. En = 0 bond is covalent. En = 1-2 bond is polar covalent. En = 3 bond is ionic. Experimental observations regarding multiple bonds: multiple bonds are shorter than single bonds. Bond length distance b/w nuclei of 2 covalently bonded atoms in a molecule: multiple bonds are stronger than single bonds. Bond strength (bond e) e required to break a bond. Exceptions to the octet rule: applies most strictly to 2nd period, 3 categories of exception. Molecules w/ < 8 valence e- (incomplete octet) Molecules w/ > 8 valence e- (expanded octet) Incomplete octet: h, group 2a & 3a: hydrogen only 2 valence e, group 2a only 4 valence e, group 3a only 6 valence e-
