Polarity is a word of three definitions. Based from the various meanings, polarity pertains to something and its opposite. For one, it can refer to the directions of a magnetic or electric field. Another would be the contradicting opinions in a debate. It can also be an interaction between organisms in biology. But, this is not what polarity means in chemistry.
In chemistry, polarity refers to either the equal sharing or unequal sharing of electrons in a covalent bond. A bond would become non-polar if the elements in the molecule share the same number of electrons. In a non-polar bond, both atoms have equal ability to pull the bonding electrons towards each other. On the other hand, those that share electrons unequally have a polar bond. In this situation, one atom has a greater ability to pull the bonding electrons towards it and is said to be more electronegative.
Bond polarity is wherein the electronegativity of the atoms are used to determine if its non-polar or polar in nature. Atoms, whether the same or different, have identical electronegativity, then that compound or molecule is non-polar. This is because the bonding electrons will be share equally among the atoms in the molecule. Besides that, atoms with different electronegativities and have a difference below 1.7 or 1.8, then that compound is polar in nature. Why is this so? The more electronegative an atom has a greater share of the bonding electrons than the less electronegative atom. The more electronegative atom has a partial negative charge, and the less electronegative atom has a partial positive charge; thus resulting to unequal pull of electrons.
Polarity of molecules is different from bonding polarity. Actually, the polarity of molecules depends on its bond polarity. It determines the net dipole of the electrons between the atoms. Polar bonds tend to have a value or net dipole, while non-polar bonds have a net dipole of zero. This is because, in a non-polar bond, the pull of the electrons are equal and from opposite sides; making the pulls between the atoms cancel out.
Life can be like polar and non-polar bonds. In biology, the cells in our body relies on polar and non-polar bonds. For example, the fatty acids are non polar and phosphate is polar; thus membranes are formed through the fatty acids dislike of water, which means they are attracted to each other in a way whereby the fatty acid tails are shielded in an outer barrier of phosphate, which form a membrane. Our lives can be like polar and non-polar bonds. There are periods in our lives that we have to cope with the hardships and another time we enjoy life’s blessings.