What do you understand by bond pairs and lone pairs of electrons? Illustrate by giving six examples

Bond pairs (also called bonding pairs) are pairs of electrons shared between two atoms in a covalent bond; lone pairs (non-bonding pairs) are pairs of electrons that belong to one atom only and are not shared. Examples follow.

• The electrons in atoms exist in pairs in orbitals. In covalent bonding, one electron from each atom forms a pair that is shared. That is a bond pair. The remaining electron pairs that are not shared and belong to a single atom are lone pairs or non-bonding pairs.
• Bond pairs cause atoms to join (molecule formation). Lone pairs influence molecular shape and reactivity (via VSEPR theory, electron repulsion, lone-pair effects).

Examples (six):

1. Water (H₂O): The oxygen has two bond pairs (one with each H) and two lone pairs.
2. Ammonia (NH₃): The nitrogen has three bond pairs (to three H) and one lone pair.
3. Methane (CH₄): Carbon has four bond pairs (to four H) and no lone pairs.
4. Chlorine molecule (Cl₂): Each Cl has one bond pair (shared between them) and three lone pairs on each Cl.
5. Nitrogen molecule (N₂): The two N atoms share three bond pairs (a triple bond) and each N has one lone pair.
6. Carbon dioxide (CO₂): The carbon is bonded by two double bonds (two bond pairs to each O) and no lone pair on carbon, each O has two lone pairs.

Thus you see how both bond pairs and lone pairs determine structure, bonding, and geometry of molecules.