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Why is water a polar molecule?

In this video, we'll explain simply why a water molecule is polar and it also has a bent shape.
Oxygen combines with 2 hydrogens in order to make 1 water molecule.

A water molecule, on the whole, is neutral. However, the electrons are not distributed evenly across the molecule and this causes the ends to be slightly charged.

Water has a lone pair of electrons

    • When oxygen bonds with hydrogen, oxygen attract electrons more strongly than hydrogen because of the higher electronegativity charge. The charge is caused by the protons - the positively charged protons in the nucleus attract the negatively charged electrons.
    • Because of the stronger electronegative force in oxygen (oxygen has more protons than hydrogen), it causes the bonding pair of electrons to be held closer to the oxygen atom.
    • The electrons are not equally shared and this results in oxygen having a slightly negative charge while the hydrogen has a slightly positive charge.
    • This separation of charges is termed dipole moment.

Water has a bent shape

Water is a bent shape

    • The lone pair of electrons in the oxygen atom are not bonded to any atoms and the pairs of electrons repulse each other.
    • These repulsive forces act to push the hydrogen atoms closer together and create a compression angle of 104º.
    • Due to the special bent shape of the water molecule, this causes the water molecules to build crystal structure when water freezes.
    • Hence water has a unique nature of expanding when it freezes.