Chemical bonding 5

VESPR theory

1. electron pairs in the valence shell of the central atom arrange themselves as far as possible to minimise repulsion and maximise stability

2. lone pair-lone pair repulsion > lone pair-bond pair repulsion > bond pair-bond pair repulsion

3. a central atom, which is more electronegative, will give rise to a larger electronic repulsion between 2 bond pairs — larger bond angle

4. a multiple bond can be considered to be like a single bond

structure showing shape & bond angle of covalent molecules

explain difference in bond angle for molecules with same structure

1. state more electronegative atom — bond pairs of (molecule) drawn closer to the __ central atom

2. higher/lower electron density around __ — greater/lesser electron repulsion

3. hence bond angle is larger/smaller than __

polar molecule

have polar bonds and have a net dipole moment (dipole moments do not cancel out)

non-polar molecules

does not have polar bonds or have polar bonds but no net dipole moment