In chemistry, there are two types of molecules. One is called a polar molecule. Another type called nonpolar molecules. In this blog post, we discuss the overview of polar vs nonpolar molecules. Why are these entities of molecules different from each other? what characteristics make them so peculiar?
What is polar molecule?
At first, we only see the simple molecules and organic molecules. The best available simple molecule in nature is water molecule. It is abundant in nature.
Water molecule contains one oxygen atom and two hydrogen atom. Hydrogen atom is the smallest atom in the periodic table. Which has only one electron and one proton on its credit.
Oxygen atom is bigger than Hydrogen atom. Oxygen atom is 8 times bigger in size than Hydrogen atom in their atomic weight. In chemistry of molecules and atoms, we deals with the electron in the outermost orbitals.
Oxygen contain around eight electrons. But all the electrons are not in the outermost shell. Some of them in the core shell of the atom, which are most stable in nature.
What is the stability of the atom?
Generally, expect noble atoms other atoms are not stable. What is noble atoms? It is lying in the last column of the periodic table. They are chemically inert in nature.
If you want to induce the chemical reactivity in noble atoms, you need to bombard with huge amount of energy. At the higher energy only, it shows some extend of reactivity.
Chemical reactivity starts from the exchange of electron between the atoms. Here, we are discussing only about the covalent bonds. This bonds are formed due the mutual sharing of electrons between the atoms.
To remove the electron from the outermost shell of noble atom is not that easy. Because they reached the stable electronic configurations.
What is stable electronic Configuration in atom?
In the outermost orbital electrons of the atom, it can either half filled or completely filled configuration. In these two states, they shows very good stability.
To remove outermost electrons from the atom, we need to give energy. That leads chemical reaction into endothermic in nature. If atoms want to combine the electrons, it will release the excess of energy into the surrounding environment. Then the chemical reaction is called exothermic in nature.
That some atoms are stable in nature. we need to give energy to remove the electron from its outermost orbital. That means the atom is staying in the lowest most electronic energy ground state. In other case, some other atoms are not stable, which staying in the higher energy state.
There are two possible unstable atom, one is losing electron to gain the stability. Another one gaining electron to achieve the stability. For example, Hydrogen atom gain stability by losing its one outermost electron. Oxygen atom attains it’s by gaining or attracting electron in the outermost orbital.
By doing losing and gaining electrons in the outermost orbital, it configured as same as the noble elements of periodic table.
This pushing and pulling game in the molecule varies depending on the presence of different group atoms.
Three categories of elements in the periodic table:
Some element in the periodic table loses its outermost orbital electrons very easily. These elements are called as metals. First two column of periodic table named as alkali metals and alkali earth metals.
These metals are not non transition metals. They are not magnetically active and not stable metals. They reacts faster in water as compare to transition metal.
They are located in the middle part of the periodic table. Most of these metals showed some kind of peculiar properties. They are magnetically active materials and good conducting materials.
They located on the right side of the periodic table. They are different than metal. They don’t like to give their outermost electrons. They always try to pull electrons from other atoms. This property is called electro-negativity.
This behaviour of atoms creates polarity. Metals are losing easily their outer most electron. Another side, non-metal are pulling others electron towards itself. This push-pull creates dipole moment or polarity in the molecules.
What is dipole moment in the molecule:
In the molecule, bonds are formed due to the sharing of the electron between the atom. The resultant charge separation between the bond distance of the molecule gives dipole moment.
Polar vs nonpolar bonds
Bond plays very important role in chemistry. There are different types of bonds in chemistry. Bonds can be listed as follows.
- Covalent Bond
- Ionic Bond
- Coordination Bond
- Metallic Bond
- Ionic Bond
- Hydrogen Bond
Our topic of discussion in polarity, we are not focusing on bond. We can discuss about bond as a different topic in our upcoming post. Now bond plays very important role in the polarity of the molecule.
For example, if two like atoms are bonded together and forms a covalent bond, then their polarity canceled each other. The net polarity of the molecule becomes zero. This molecule acts as a non-polar molecule.
If a high electronegative atom bonded with a more electropositive atom, then the electronegative atom tries to pull the electron from an electropositive atom. The net polarity of the molecule becomes non-zero. This acts as a polar molecule.
CCl4 polar or nonpolar (polar vs nonpolar) :
Carbon atom valency is four. It is bonded with four chlorine atom. Chlorine atoms are much more electronegative than carbon atom.
Two chlorine atoms pulls the electron one side, another two chlorine pulls in the opposite side. Finally, it canceled each other. CCl4 molecule acts as nonpolar molecule.
Is CH4 polar or nonpolar (polar vs nonpolar) :
CH4 molecule, carbon in the center of the molecule with symmetrical tetrahedral structure. Four hydrogen atoms boned with this center carbon atom.
The electronegativity of carbon and hydrogen is 2.55 and 2.2, respectively. There is no much difference in their electronegativity.
All four C-H covalent bonds are identical. The final polarity of the CH4 molecule is zero. It is a nonpolar molecule.
Is HBr polar or nonpolar (polar vs nonpolar) :
It is very simple diatomic molecule. Bromine (Br) atom is much more electronegative than hydrogen atom.
It creates a high polarity difference in the HBr molecule. HBr is a polar molecule.
Is HCl polar or nonpolar (polar vs nonpolar) :
Diatomic molecule of chlorine and hydrogen. Chlorine (Cl) atom is much more electronegative than hydrogen atom.
This created a high polatrity difference in HCl molecule. HCl is a polar molecule.
Is SF6 polar or nonpolar (polar vs nonpolar):
In nature, SF6 is a nonpolar compound since, according to VSEPR theory, six fluorine atoms are arranged symmetrically with the sulphur atom, cancelling out the dipole moment of the S-F bond, rendering it a nonpolar compound.
Is BeCl2 polar or nonpolar (polar vs nonpolar) :
Is BeCl2 a polar or nonpolar substance? Because of its symmetrical (linear-shaped) geometry, BeCl2 (Beryllium chloride) is non-polar.
Despite the fact that the Be-Cl bond is polar and has some net dipole, the overall BeCl2 molecule is non-polar since the dipoles of both Be-Cl bonds are equal and opposite and cancel each other out, resulting in a zero dipole moment.
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FAQ on Polar vs Nonpolar
Why is SF4 polar and SF6 nonpolar?
The lone pair forces the molecular geometry of SF4 into a see-saw form, according to VSEPR theory. Two S-F bonds are pointed in opposite directions, and their bond dipoles cancel. The other two S-F dipoles, on the other hand, are pointing “under.” The molecule is polar and their bond dipoles do not cancel.
Is N2 polar or nonpolar?
Is N2 polar or nonpolar, then? Because of its linear geometrical composition, N2 is a nonpolar molecule that is also a diatomic molecule. As a consequence, all atoms have equal electronegativity and share an equal proportion of charge, resulting in a nonpolar molecule with a net-zero dipole moment.
Is PCl3 a polar molecule?
Phosphorus trichloride is a chemical compound of three chlorine atoms and one phosphorus atom, each with one lone pair. The PCl3 molecule is polar in nature due to its asymmetric form and difference in electronegativity.
Why PCl5 is non polar But PCl3 is polar?
The molecule has a dipole moment and is polar since it is not symmetrical. PC, on the other hand. This molecule has no dipole moment and is non-polar due to its symmetry.
Why the dipole moment of becl2 is zero?
BeCl2 is a linear molecule with an 180 degree bond angle. As a force and a vector quantity, the net dipole will be zero if two polar bonds are equal and opposite in orientation.
How do you know if it is polar or nonpolar?
Determine whether each bond is polar or nonpolar. (A bond is considered polar if the difference in electronegativity between the atoms in it is greater than 0.4.) The bond is practically nonpolar if the difference in electronegativity is less than 0.4.) The molecule is nonpolar if there are no polar bonds.