A polar covalent bond is a type of covalent bond in which the two bonding atoms do not share the same number of electron(s). This tendency to attract more electrons is due to one of the atoms being more electronegative in nature.
Atoms with higher electronegativity – the ability or affinity to attract more electrons – are the dominant atoms in a polar covalent bond. As a result, the atom gaining more electrons gets a higher negative charge and the other atom acquires partial positive charge. The difference in electronegativity between the bonds ranges between 1.7 and 4 on the periodic table, with electronegativity less than 1.7 being referred to as non-polar.
H2O (water) molecule is based on the polar covalent bonding mechanism, involving two hydrogen atoms and a single oxygen atom. In this chemical bond, the oxygen atom gets eight electrons since it has a stronger pull, which gives the element a slightly higher negative charge.