What is a covalent bond and how is it formed?

A covalent bond is a type of chemical bond formed when two atoms share a pair of electrons.

In more detail, a covalent bond is one of the primary types of bonding in chemistry, alongside ionic and metallic bonds. It is formed when two non-metal atoms share a pair of electrons. This sharing allows each atom to achieve a full outer shell of electrons, which is a stable configuration. The shared pair of electrons is attracted to the nuclei of both atoms, which holds the atoms together and forms the bond.

The formation of a covalent bond involves the overlap of atomic orbitals. Each atomic orbital can hold a maximum of two electrons. When two atoms come close together, their atomic orbitals overlap, allowing the electrons to exist in the region of overlap. This overlap of orbitals and sharing of electrons is what forms a covalent bond.

Covalent bonds can be single, double, or triple, depending on the number of electron pairs being shared between the atoms. For example, in a molecule of oxygen (O2), there is a double covalent bond, meaning two pairs of electrons are shared. In a molecule of nitrogen (N2), there is a triple covalent bond, with three pairs of electrons being shared.

The strength of a covalent bond depends on the distance between the nuclei of the two atoms (bond length) and the number of electron pairs being shared (bond order). The shorter the bond length and the higher the bond order, the stronger the covalent bond.

Covalent bonding is a crucial concept in chemistry as it explains how many substances, including water, carbon dioxide, and organic molecules, are held together. Understanding covalent bonding can help you predict the properties of these substances, such as their boiling and melting points, solubility, and electrical conductivity.