Answer:
Diatomic molecules will be nonpolar when they are composed of only one element
Explanation:
A diatomic molecule of a single element like X-X will be nonpolar due to lack of polarization of bonding electrons.
Bond exist between two X atoms will have no polarization because both X atoms have same electronegativity. Therefore both of them attracts bonding electrons towards themselves equally and in opposite direction.
So bonding electrons remain in equal distance from both X nucleus resulting no polarization and hence the diatomic molecule is nonpolar.
