(i) Covalent or molecular bond: A chemical bond formed between two atoms by mutual sharing of one or more pairs of electrons. Depending on the number of shared electron pairs, the bond can be single (-), double (=), or triple (≡).
(ii) Covalent or molecular compound: A compound formed by the mutual sharing of electrons between atoms, resulting in covalent bonds.
(iii) Covalency: The number of electron pairs an atom shares with other atoms to achieve a stable electronic configuration. For example, the covalency of hydrogen is 1, oxygen is 2, and nitrogen is 3.
(iv) Shared pair of electrons: A pair of electrons shared between two atoms that forms a covalent bond.
