MIDTERM 3 - Steric Number and Geometric Rules

SN = 2

Hybridization: sp
Electron Geometry: Linear (no molecular geometric variants)

SN = 3

Hybridization: sp2
Electron Geometry: Trigonal Planar

SN = 4

Hybridization: sp3
Electron Geometry: Tetrahedral

SN = 5

Hybridization: sp3d
Electron Geometry: Trigonal Bipyramidal

SN = 6

Hybridization: sp3d2
Electron Geometry: Octahedral

Molecular Geometric Variants when SN = 3

1 lone pair: Bent

Molecular Geometric Variants when SN = 4

1 lone pair: trigonal pyramidal
2 lone pairs: Bent

Molecular Geometric Variants when SN = 5

1 lone pair: See-saw
2 lone pairs: T-Shaped
3 lone pairs: Linear

Molecular Geometric Variants when SN = 6

1 lone pair: Square Pyramidal
2 lone pairs: Square Planar

Dead giveaways of a Polar molecule

1) the molecule contains a Hydrogen bond
H—O, H—F, H—N

2) lone pairs exist asymmetrically on the central atom (odd number of lone pairs)

3) different elements exist on the sides of the central atom

Electron Geometries with 90 degree bond angles (IDEAL)

trigonal bipyramidal (axial plane)

octahedral

Electron Geometries with 109.5 degree bond angles (IDEAL)

tetrahedral

Electron Geometries with 120 degree bond angles (IDEAL)

trigonal planar

trigonal bipyramidal (equatorial plane)

Electron Geometries with 180 degree bond angles (IDEAL)

linear

Polar Molecular Shapes

Bent, Tig Pyramidal, Tetrahedral, Square Pyramidal, See-Saw