NOBr Lewis structure

NOBr (nitrosyl bromide) has one nitrogen atom, one oxygen atom, and one bromine atom.

In NOBr Lewis structure, there is a double bond between nitrogen and oxygen atom, and a single bond between nitrogen and bromine atom. The oxygen atom has two lone pairs, the nitrogen atom has one lone pair, and the bromine atom has three lone pairs.

Alternative method: Lewis structure of NOBr

Contents

Rough sketch

First, determine the total number of valence electrons

In the periodic table, nitrogen lies in group 15, oxygen lies in group 16, and bromine lies in group 17.

Hence, nitrogen has five valence electrons, oxygen has six valence electrons, and bromine has seven valence electrons.

Since NOBr has one nitrogen atom, one oxygen atom, and one bromine atom, so…

Valence electrons of one nitrogen atom = 5 × 1 = 5
Valence electrons of one oxygen atom = 6 × 1 = 6
Valence electrons of one bromine atom = 7 × 1 = 7

And the total valence electrons = 5 + 6 + 7 = 18

Learn how to find: Nitrogen valence electrons, Oxygen valence electrons, and Bromine valence electrons

Second, find the total electron pairs

We have a total of 18 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the total electron pairs = 18 ÷ 2 = 9

Third, determine the central atom

We have to place the least electronegative atom at the center.

Since nitrogen is less electronegative than oxygen and bromine, assume that the central atom is nitrogen.

Therefore, place nitrogen in the center and oxygen and bromine on either side.

And finally, draw the rough sketch

NOBr Lewis Structure (Step 1) — Rough sketch of NOBr Lewis structure | Image: Learnool

Lone pair

Here, we have a total of 9 electron pairs. And two bonds are already marked. So we have to only mark the remaining seven electron pairs as lone pairs on the sketch.

Also remember that both (nitrogen and oxygen) are the period 2 elements, so they can not keep more than 8 electrons in their last shell. And bromine is a period 4 element, so it can keep more than 8 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are oxygen and bromine.

So for oxygen and bromine, there are three lone pairs, and for nitrogen, there is one lone pair.

Mark the lone pairs on the sketch as follows:

NOBr Lewis Structure (Step 2) — Lone pairs marked on NOBr Lewis structure | Image: Learnool

Formal charge

Use the following formula to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

For nitrogen atom, formal charge = 5 – 2 – ½ (4) = +1

For oxygen atom, formal charge = 6 – 6 – ½ (2) = -1

For bromine atom, formal charge = 7 – 6 – ½ (2) = 0

Here, both nitrogen and oxygen atoms have charges, so mark them on the sketch as follows:

NOBr Lewis Structure (Step 3) — Formal charges marked on NOBr Lewis structure | Image: Learnool

The above structure is not a stable Lewis structure because both nitrogen and oxygen atoms have charges. Therefore, reduce the charges (as below) by converting lone pairs to bonds.

Convert a lone pair of the oxygen atom to make a new N — O bond with the nitrogen atom as follows:

NOBr Lewis Structure (Step 4) — Lone pair of oxygen is converted, and got the stable Lewis structure of NOBr | Image: Learnool

Final structure

The final structure of NOBr consists of a central nitrogen atom linked to one oxygen atom and one bromine atom. In this arrangement, the nitrogen atom satisfies the octet rule by forming a double covalent bond with the oxygen atom and a single covalent bond with the bromine atom, while retaining one lone pair. Within this layout, the oxygen atom fulfills its octet by maintaining two lone pairs alongside its double bond, and the bromine atom reaches a stable octet by keeping three lone pairs. This configuration represents the most stable state for the molecule because it results in a formal charge of zero for every atom involved. Accordingly, this specific electronic distribution serves as the definitive and most accurate Lewis representation of nitrosyl bromide.

Next: BH₄^– Lewis structure

External video

NOBr Lewis Structure – How to Draw the Lewis Structure for Nitrosyl Bromide – YouTube • Wayne Breslyn

External links

Deep

Learnool.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.