1.5 Describing Chemical Bonds: Valence Bond Theory

Covalent bond

A bond formed when two atoms share electrons.

Valence Bond Theory

A model that describes covalent bonding as the overlap of singly occupied orbitals from two atoms.

Sigma bond (σ bond)

A type of covalent bond formed by the head-on overlap of atomic orbitals, resulting in cylindrical symmetry.

Bond strength

The amount of energy required to break a bond, measured in kJ/mol.

Bond length

The optimum distance between the nuclei of two bonded atoms where maximum stability occurs.

Overlap of orbitals

The interaction of singly occupied orbitals from two atoms, leading to electron pairing and bonding.

H–H bond

The covalent bond formed between two hydrogen atoms through the overlap of their 1s orbitals.

Energy release in bond formation

The process of forming a bond releases energy, making the resulting molecule more stable than the individual atoms.

Optimum distance between nuclei

The distance where nuclei are close enough to share bonding electrons but not so close that they repel each other.

Energy conversion

1 kJ = 0.2390 kcal; 1 kcal = 4.184 kJ, used for energy measurements in chemistry.