NH3 (Ammonia) is a covalent (polar covalent) compound because when one nonmetal combines with another nonmetal, it usually forms a covalent compound. Here, N is a nonmetal and H is also a nonmetal. So when they combine, it forms a covalent compound.
Well, now you have got to know that NH3 is a covalent compound, but let me explain the in-depth reason why NH3 is a covalent compound.
If you are a visual learner like me, then here is a short one minute video for you.
Why is NH3 a Covalent compound?
As mentioned above, you can simply remember that when the nonmetal combines with another nonmetal, the bond between them is a covalent bond.
Here in NH3, the N atom is a nonmetal and the H atom is also a nonmetal.
Hence the bond between them is a covalent bond.
How does the covalent bond form between N and H?
In NH3, there are two atoms;
N and H.
About Nitrogen (N):
Nitrogen atom have 7 electrons.
The electrons arrangement in Nitrogen (N) is 2, 5.
So the outermost orbit of Nitrogen atom has 5 electrons.
Now in order to achieve a stable octet, the Nitrogen atom needs 3 more electrons.
Hence during the chemical reaction, the Nitrogen atom will gain 3 electrons from the combining atom to form a stable octet.
About Hydrogen (H):
Hydrogen atom have 1 electron.
It has only 1 orbit and there is only 1 electron in this orbit.
Now in order to achieve a stable duplet, the Hydrogen atom needs 1 more electron.
Hence during the chemical reaction, the Hydrogen atom will gain 1 electron from the combining atom to form a stable duplet.
What happens when N and H combine?
When N and H combine with each other, the Nitrogen atom and Hydrogen atoms mutually share their 1-1 electrons with each other.
Because of this the hydrogen atom will have 2 electrons in its outermost orbit and similarly the nitrogen atom will also have 8 electrons in its outermost orbit.
As a result, the hydrogen atom will have a stable duplet and the nitrogen atom will have a stable octet.
And finally, as the bond formed between the nitrogen and hydrogen is due to the mutual sharing of electrons, it is considered a covalent bond.
Thus, NH3 is a covalent compound.
Is NH3 polar covalent or nonpolar covalent?
In order to know whether NH3 is a polar covalent molecule or nonpolar covalent molecule, we have to check the electronegativity difference of the combining atoms.
If the electronegativity difference (ΔEN) is less than 0.4, then the bond is nonpolar covalent bond.
If the electronegativity difference (ΔEN) is between 0.4 to 1.7, then the bond is polar covalent bond.[1][2][3][4]
Now the electronegativity of Nitrogen and Hydrogen are mentioned below. (You can see the electronegativity of all the elements from this electronegativity chart).
- Electronegativity of Nitrogen (N) = 3.04
- Electronegativity of Hydrogen (H) = 2.2
So for NH3, the electronegativity difference (ΔEN) = 3.04 – 2.2 = 0.84
This value lies between 0.4 to 1.7, which indicates that the bond between Nitrogen (N) and Hydrogen (H) is polar covalent bond.
But the NH3 molecule has 1 lone pair which results in an asymmetric shape of the entire NH3 molecule.
Because of this asymmetric shape there are positive and negative poles of charges on the overall molecule of NH3.
Hence, NH3 (ammonia) is a polar covalent molecule.
I hope you have understood the reason why NH3 is a polar covalent compound.
Check out other compounds to see whether they are ionic or covalent;
Is CH4 (Methane) Ionic or Covalent?
Is MgCl2 (Magnesium chloride) Ionic or Covalent?
Is SO2 (Sulfur dioxide) Ionic or Covalent?
Is MgO (Magnesium oxide) Ionic or Covalent?
Is CCl4 (Carbon tetrachloride) Ionic or Covalent?
Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. With a desire to make learning accessible for everyone, he founded Knords Learning, an online learning platform that provides students with easily understandable explanations.
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