We left three possible situations out of Table 6.2:

1. Four electron groups (SN = 4): one bonding group and three lone pairs.

2. Three electron groups (SN = 3): one bonding group and two lone pairs.

3. Two electron groups (SN = 2): one bonding group and one lone pair.

These are considered trivial cases. Why? What shape(s) do these bonding situations give rise to?

Transcribed Image Text:

Table 6.2 VSPER Molecular Shape Table Four electron groups (SN = 4) Molecular shape Electron-group arrangement 109.5⁰ Four bonding groups Tetrahedral No lone pairs Tetrahedral Bond angles all 109.5⁰ Three bonding groups Pyramidal One lone pair Tetrahedral Bond angles compressed to ~107° by lone pair* -105° Two bonding groups Two lone pairs Tetrahedral Bent Bond angle compressed to ~105° by lone pair* Three electron groups (SN = 3) Electron-group Molecular arrangement shape 120° Three bonding groups No lone pairs Trigonal planar Trigonal planar Bond angles all 120° -118° Two bonding groups One lone pair Trigonal planar Bent Bond angle compressed to ~118° by lone pair* Two electron groups (SN = 2) Electron-group Molecular shape arrangement 180° Two bonding groups No lone pairs Linear Linear Bond angle 180° Key: SN = Steric Number = # of electron groups = # attached atoms and # of ion pairs around central atom Central atom Bonding electron group (single, double, or triple covalent bond) Lone pair of electrons