Covalent bond or covalency same hota h 

"Covalent bond" and "covalency" are both terms used in chemistry, but they have slightly different meanings:

1. Covalent Bond: This is a chemical bond where two atoms share their electrons to form a stable compound. This bond forms when two atoms share their electrons to complete their outer energy level.

2. Covalency: This term refers to the number of covalent bonds that an atom in a compound can form. It indicates the capacity of an atom to form covalent bonds. For example, carbon has a covalency of 4 because it can form four covalent bonds.

Thus, "covalent bond" refers to a specific bond, while "covalency" refers to the number of bonds that an atom can form.

In summary, "covalent bond" is a bond itself, and "covalency" is the number of such bonds that an atom can form.