In chemistry, the bonds will be shared between two atoms. There are many types of bonds available. But the two most commonly used bonds in chemistry for sharing electrons are covalent, and the other one is polar covalent. These two are further divided into types. Based on their electronegativity difference, the bond type can be found easily.
Covalent vs Polar Covalent
The main difference between Covalent and Polar Covalent is that they have a shared pair of electrons, and the electrons are in an unpaired stage, then it is called a covalent bond. Polar covalent bonds are used to name the bonds that are polar in covalent bonds. In covalent bonds, you can either see the dipole moment or cannot. But in polar covalent, you can see the dipole moment.
Covalent bonds are formed with the atoms. A bond can be identified, whether it is covalent or non-covalent, by looking at the periodic table. First, we have to identify whether the component is made of metal or nonmetals. Also, we have to find how many metals and nonmetals got involved in that bond. These statistics will help us to find whether it is covalent or not.
A polar covalent bond will be classified into two types, and they can be identified with the help of their electronegativity difference. Some of the characteristics a non-polar covalent bond should possess are the electrons should be equally shared between the atoms. In non-polar covalent, you will be able to find that the electronegativity difference between them is 0.
Comparison Table Between Covalent and Polar Covalent
| Parameters of Comparison | Covalent | Polar Covalent |
| Definition | They are chemical bonds that are created by unpaired electrons between the atoms | This is used to name the polar covalent bonds |
| Polarity | Covalent can be sometimes polar and sometimes non-polar | Polar covalent are always polar |
| Charge Separation | They can have either electronic charge separation or not | They show some slight electronic charge separation |
| Dipole moment | They can either show or they cannot | They can show the dipole moment |
| Electrons | Electrons are shared equally | Electrons are not shared equally |
What is Covalent?
It is an interatomic linkage when electronic pair is shared between two atoms. This will be formed when they have lower energy than the widespread atoms. There are three types of covalent bonds that are. It has been found that double covalent and triple covalent are stronger than single covalent bonds as they have more energy in them.
One of the best examples to describe covalent bonds is with the help of carbon dioxide molecules. This molecule has got one carbon atom and two oxygen atoms which makes it very stringer because two electron pairs are shared between them. This bonding is very important because it acts as a primary source for carbon molecules to interact and communicate with each other. They help to share electrons with other molecules.
This, in turn, will create a long chain and will allow the much-needed complexity in life. Atoms will bond with other atoms in the covalent bond so that they will be able to gain stability. Once they gain stability, they will form a full electron shell. They also share their outermost electrons, which in turn will help them to fill their outer shell so that they can gain stability. The strongest covalent bond of all the covalent bonds that are in existence is the sigma bond.
What is Polar Covalent?
Atoms that share electrons even though they are from different electronegativities are called polar covalent. The partial negative sharing will happen when the bonding pairs are unequally shared. A partial positive charge will happen, and that is based on the hydrogen atoms. The polar covalent bond will be divided into two types polar and non-polar covalent. Here the atoms will have unequal attraction, so the sharing between the electrons is unequal.
The best example of polar covalent is water. We can even find whether the bond is polar or non-polar by checking its electronegativity difference. If the electronegativity difference is less than 0.4, then they are considered to be non-polar. If the electronegativity difference is greater than 0.4, then they are considered to be polar. This is called the elements are having electronegativity higher than the other.
There are several examples available for non-polar covalent bonds, and you can find them in noble glasses and homonuclear diatomic elements. A non-polar covalent bond will be formed when they have two hydrogen atoms, and the electrons will be equally shared. SO2 bond is considered to be a polar covalent bond because you would be able to find the electronegativity difference between sulphur and oxygen atoms. In a non-polar covalent bond, the bonding will take place between two identical nonmetals.
Main Differences Between Covalent and Polar Covalent
- When the electrons are unpaired, then it is called a covalent bond. On the other hand, polar covalent is used to name the covalent bond when they are polar.
- Covalent bonds can be sometimes polar and sometimes non-polar. On the other hand, polar covalent are always polar and will not change.
- In covalent bonds, there might be electronic separation available, and sometimes they cannot be. On the other hand, in polar covalent bonds, there will be slight electronic charge separation.
- Covalent bonds can either show dipole moment or cannot. On the other hand, polar covalent will always show dipole moment.
- In covalent bonds, electrons will be shared equally. On the other hand, in polar covalent, the electrons are not shared equally.
Conclusion
Both these bond topics are available in the school chemistry curriculum. There they will learn about the types and examples so that they can classify the types with the help of their electronegativity differences. To learn more about them or want to gain in-depth knowledge in this topic, they should take the science stream in their 11th and 12th grade.
Their further topics will be involved in bonds. To gain practical knowledge, then one should take chemistry as their major subject in their higher studies. With the help of proper lab facilities in the higher studies, they will be able to do more research and gain in-depth knowledge on the topic, which will be useful for them in their research area.
References
- https://pubs.acs.org/doi/abs/10.1021/jp8106183
- https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.91.015502