Covalent bonding

The chemical bonds formed by sharing of electrons between non-metallic elements are referred to as covalent bonds. When two or more atoms are joined together chemically by covalent bonds, a molecule is formed. The mass of a molecule is called the molecular mass.

Covalent bonds may either be polar or nonpolar. When electrons in a bond are shared equally, the bond is called nonpolar bond. When electrons in a bond are shared unequally, the bond is called polar covalent bond or polar bond.

Nonpolar covalent bond

When the covalent bond is formed between two identical nonmetals, a nonpolar covalent bond is formed.

7 diatomic molecules

In total, there are seven elements that exist as diatomic molecules. These are the diatomic elements.

1. hydrogen molecule (H₂)
2. oxygen molecule (O₂)
3. nitrogen molecule (N₂)
4. fluorine molecule (F₂)
5. chlorine molecule (Cl₂)
6. bromine molecule (Br₂)
7. iodine molecule (I₂)

Polar covalent bond

When the non-metallic elements involved in the bond have different electronegativities, a polar covalent bond is formed. Examples of molecules formed by polar covalent bonds are:

1. HF
2. HCl
3. ClO₂
4. H₂O
5. NH₃

Content suitability

BCIT courses: CHEM 0011