The Lewis structure and Molecular geometry of H2O

Description

Water, one of the Earth's primary constituents, has the molecular formula H₂O. A water molecule comprises two hydrogen atoms and one oxygen atom joined by a covalent bond. Furthermore, two or more H₂O molecules join by hydrogen bonds to form a compound.

Lewis structure

The Lewis structure, also known as an electron dot structure, represents the total valence electrons in an atom that is available for bonding to create a molecule and, eventually, a compound. The Lewis structure of H₂O is shown below:

Lewis structure of water molecule contains two single bonds around oxygen atom. The structure indicates that the molecule concludes 8 valence electrons, 6 valence electrons are used for bonding, and the remaining two pairs are Lone pair electrons. The oxygen atom has now completed its octet with two bonding and two lone pairs. Moreover, by sharing a bonding pair with oxygen, each hydrogen atom has an entire valence shell of two electrons.

Molecular geometry

While these two Hydrogen atoms are symmetrically arranged in the plane, the two lone pairs of electrons on the Oxygen atom repel these atoms. Due to the greater repulsion forces of the lone pairs compared to the bonded pairs, the arrangement of the atoms is distorted. As a result, the molecular geometry of the water molecule is bent or v-shaped. The bond angle in a water molecule is 104.5°.

Hybridization

The hybridization of the H₂O molecule is sp³, as it has one s orbital and three p orbitals that combine to form four hybrid orbitals. In addition, H₂O is a polar substance. This is due to the bent shape of the water molecule, which results in an unequal charge distribution across the hydrogen and oxygen atoms. This leads to a net dipole moment in the water molecule.