3. Charge clouds

• Molecules and molecular ions come in loads of different shapes. Shape depends on number of pairs of electrons in outer shell of central atom. Pairs of electrons can be shared in covalent bond or can be unshared. Shared electrons are called bonding pairs, unshared electrons are called lone pairs or non-bonding pairs. Bonding pairs and lone pairs of electrons exist as charge cloud. Charge cloud is area where there are chances of finding an electron.
• Electrons are all negatively charged, so charge clouds repel each other until they’re far apart as possible. Shape of charge cloud affects how much it repels other charge clouds. Lone pair charge clouds repel more than bonding pair charge clouds, so bond angles are often reduced because bonding pairs are pushed together by lone pair repulsion