Water is made up of hydrogen and oxygen combined in the ration 2:1 by volume. Thus, the molecular formula of water is H2O. in a molecule of water, one oxygen atom is bonded to two hydrogen atoms and the two O-H bonds are inclined to each other atomic an angle of 104.5°. Thus, H2O has been a bent structure.
Polarity of water molecule:
In a water molecule, one oxygen atom forms bonds with two hydrogen atoms by sharing of electrons as shown above. Thus, oxygen atom shares one electron pair with each hydrogen atom. Oxygen is more electronegative than hydrogen. So, oxygen atom pulls the shared pairs of electrons towards it. This leads to a small negative charge on the oxygen atom and small positive charges on the two hydrogen atoms. This make water molecule develop polarity. In other words, water molecule is a polar molecule.