What is the dipole moment in a molecule? Describe the dipole moment of diatomic molecules.

(N/A) The dipole moment of a molecule is the resultant dipole moment of all individual bonds. Its magnitude depends on the individual bond dipole moments and their spatial arrangement.
Dipole moment of diatomic molecules: All diatomic molecules are linear. They are classified into two types:
$(i)$ Homonuclear molecules $(A_2)$
$(ii)$ Heteronuclear molecules $(AB)$

Homonuclear $(A_2)$	Heteronuclear $(AB)$
e.g.,$H_2, F_2, Cl_2, Br_2, I_2, O_2, N_2$	e.g.,$HF, HCl, HBr, HI, CO, NO$
$\mu = 0 \ D$ (Non-polar)	$\mu \neq 0$ (Polar)
Bonding electron pair is shared equally between atoms.	Bonding pair is localized towards the more electronegative atom $(A^{+\delta}-B^{-\delta})$.

$(iii)$ As the electronegativity difference between two atoms increases,ionic character increases and covalent character decreases.

Molecule	$HF$	$HCl$	$HBr$	$HI$	$H_2$
$\mu \ (D)$	$1.78$	$1.07$	$0.79$	$0.38$	$0.00$