NBr3 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 Br is also a nonmetal. So when they combine, it forms a covalent compound.
Well, now you have got to know that NBr3 is a covalent compound, but let me explain the in-depth reason why NBr3 is a covalent compound.
Why is NBr3 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 NBr3, the N atom is a nonmetal and the Br atom is also a nonmetal.
Hence the bond between them is a covalent bond.
How does the covalent bond form between N and Br?
In NBr3, there are two atoms;
N and Br.
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 Bromine (Br):
Bromine atom have 35 electrons.
The electrons arrangement in Bromine (Br) is 2, 8, 18, 7.
So the outermost orbit of Bromine atom has 7 electrons.
Now in order to achieve a stable octet, the Bromine atom needs 1 more electron.
Hence during the chemical reaction, the Bromine atom will gain 1 electron from the combining atom to form a stable octet.
What happens when N and Br combine?
When N and Br combine with each other, the Nitrogen atom and Bromine atoms mutually share their 1-1 electrons with each other.
Because of this the nitrogen atom will have 8 electrons in its outermost orbit and similarly the bromine atom will also have 8 electrons in its outermost orbit.
As a result, the nitrogen atom as well as bromine atom will have a stable octet.
And finally, as the bond formed between the nitrogen and bromine is due to the mutual sharing of electrons, it is considered a covalent bond.
Thus, NBr3 is a covalent compound.
Is NBr3 polar covalent or nonpolar covalent?
In order to know whether NBr3 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.
Now the electronegativity of Nitrogen and Bromine are mentioned below. (You can see the electronegativity of all the elements from this electronegativity chart).
- Electronegativity of Nitrogen (N) = 3.04
- Electronegativity of Bromine (Br) = 2.96
So for NBr3, the electronegativity difference (ΔEN) = 3.04 – 2.96 = 0.08
This value is less than 0.4, which indicates that the bond between Nitrogen (N) and Bromine (Br) is a nonpolar covalent bond.
But the NBr3 molecule has 1 lone pair which results in an asymmetric shape of the entire NBr3 molecule.
Because of this asymmetric shape there are positive and negative poles of charges on the overall molecule of NBr3.
Hence, NBr3 is a polar covalent molecule.
I hope you have understood the reason why NBr3 is a polar covalent compound.
Check out other compounds to see whether they are ionic or covalent;
Is NaCl (Sodium chloride) Ionic or Covalent?
Is CO2 (Carbon dioxide) Ionic or Covalent?
Is H2O (Water) Ionic or Covalent?
Is Hydrogen chloride (HCl) Ionic or Covalent?
Is CaCl2 (Calcium chloride) 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 chemistry learning platform that provides students with easily understandable explanations.
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