Bonding and Chemical Interactions

Exceptions to octet rule

some elements stable with fewer than 8 electrons: H (2), He (2), Li (2), Be (4), B (6), atoms at or beyond 3rd period can have more than 8 valence

Formal charge

valence - dots - sticks

polar covalent bond

bonding electron pair is not shared equally, but pulled more towards electronegative atom

2 regions of electron density

linear

3 regions of electron density

trigonal planar

4 regions of electron density

tetrahedral

5 regions of electron density

trigonal bipyramidal

6 regions of electron density

octahedral

3 regions of electron density, one lone pair

bent

4 regions of electron density, one lone pair

trigonal pyramidal

4 regions of electron density, 2 lone pairs

bent

5 regions of electron density, one lone pair

seasaw

5 regions of electron density, two lone pairs

T-shape

5 regions of electron density, three lone pairs

linear

6 regions of electron density, one lone pair

square pyramidal

6 regions of electron density, two lone pairs

square planar

6 regions of electron density, three lone pairs

T-shaped

6 regions of electron density, four lone pairs

linear

Ligands

donor molecules use coordinate covalent bonds

Hydrogen bonding

partial positive of H atom interacts with partial negative of FON nearby

Dipole-dipole interactions

polar molecules orient themselves so positive region is close to negative of another

Dispersion forces

bonding electrons can be located randomly anywhere in orbital, causes unequal share of electrons