Question

Why share pair of electrons are formed in the case of covalent compounds ?

Answer 1

1.catenation
2.tetravalency

Answer 2

Electrons in a polar covalent bond are shifted toward the more electronegative atom; thus, the more electronegative atom is the one with the partial negative charge. The greater the difference in electronegativity, the more polarized the electron distribution and the larger the partial charges of the atoms.