Covalent Bonds : Definition, Bond length, Bond strength

Rucete ✏ Chemistry In a Nutshell

Covalent Bonds

Covalent Bonds

1 A bond in which two electrons are shared by two atoms.

2 A molecular concept (Molecule) is used to represent covalent bond.

3 Only contained by Nonmetals.

4. Multiple Bonds in Covalent Bonding
 1. Single bond : represent as (-), one shared electron pair
 2. Double bond : represent as (=), two shared electron pairs
 3. Triple bond : represent as (≡), three shared electron pairs

5 The electrons that are shared in a covalent compounds are applicable only to the valance(outer) electrons.


6 Non-bonding electrons or lone pairs means an electron in which atoms between atoms do not share electrons.

Bond Length

1 Distance between the nuclei of two bonded atoms in a molecule.

2 Bond length
 Single bond > Double bond > Triple bond

Bond strength

1 It is determined by the amount of energy required to break a covalent bond

2 Bond energy (B.E.)
 The amount of energy required to break each bond in a mole of gas.

3 ΔH° = Σ B.E (reactants) - Σ B.E (products)

 1. ΔH° > 0 : endothermic reaction
 2. ΔH° < 0 : exothermic reaction