Electronegativity is described as an atom's ability to attract electrons. When atoms of varying electronegativity share electrons, the electrons have an unequal distribution of charge. Atoms with unequal charge distribution are called polar molecules.
When the charge of both atoms is equally distributed, the molecule is said to be non-polar.
Polar molecules have an asymmetrical structure due to the difference in negative and positive charge found throughout the molecule. Portions of polar molecules with opposite charges attract and like charges repel. Non-polar molecules have a symmetrical structure due to equal distribution of charge.
The mass of a molecule, whether it is polar or non-polar, is based on the quantity of protons and neutrons in its structure. Each proton and neutron has a mass of 1amu.
Carbon has 6 protons, 6 neutrons, and 6 electrons. If you add the number of protons and neutrons in carbon's nucleus, you can conclude that carbon has a mass of 12amu.
This is an image of a polar molecule.
