What is polar and non-polar?
Polar molecules must grasp polar bonds due to a distinction in electronegativity between the bonded atoms. A polar molecule having two or more polar bonds formed an asymmetric geometry so that the bond dipoles do not cancel each other effects.
Polar molecules magnetize each other in the course of dipole–dipole intermolecular forces and hydrogen bonds. Polarity induce a number of physical properties for example surface tension, solubility, melting and boiling points of Polar molecules.
Example of polar molecules are Ammonia (NH3), Sulfur Dioxide (SO2) and Hydrogen Sulfide (H2S) etc.
A molecule is known as nonpolar either due to an equal sharing of electrons among the two atoms of a diatomic molecule or due to the symmetrical arrangement of polar bonds in most complex molecules. Examples of non ploar molecules are; Nitrogen (N2), Oxygen (O2), Carbon Dioxide (CO2), Methane (CH4), Ethylene (C2H4) etc.
Is NO2 Polar or Non-Polar?
Here are some points which shows that NO2 is polar molecule.
Geometry of the Molecule:
We can say NO2 is a polar molecule. When we draw structure of NO2 geometry of the molecule is bent due to non-bonding pair of electrons. The bent geometry induce the polarity.
If the NO2 molecule had linear geometry, the polar bonds would cancel each other effect and the molecule would be non-polar but here situation is opposite , a lone pair of electrons is also present on nitrogen. The pair of electrons repel the bonds due to high repulsive forces of lone pairs the moleculer geometry distort and formed bend geometry. The polar bonds do not negate each other, assemblage the polar molecule.
Electronegativity difference also create polarity. The polarity of the bond can be calculated by noting the electronegativity difference of bonded atoms: If electronegativity difference of two atoms is from 0.4 to 1.7 then the polar bond formed. If the electronegativity difference of two atoms is less than 0.4, then it formed non polar bond.
E.N of Nitrogen = 3.04
E.N of Oxygen = 3.44
Electronegativity difference =3.44-3.04
0.4 is Electronegativity difference it shows that NO2 is polar molecule.
Oxygen is more electronegative than nitrogen and pulls the electrons from the bonds surroundings. They are unequally dispersed. Therefore, it formed a N-O polar bond with the oxygen negative and the positive charge on nitrogen.
Bond polarity take place when the electron density build up towards one end of a bond, due to which slight negative charge take place at that end and the other end a slight positive charge automatically. This happened because of a difference in electronegativity of the two atoms that share the electrons.
Nitrogen formed 3 covalent bonds, with one remaining lone pair giving its geometry more tetrahedral than planar, so that even if you had 3 similar elements bonded to it, there would be asymmetry consequently giving it minor polarity.
Related: h3o+ polar or non-polar