# NH4+ Lewis structure

NH4+ (ammonium) has one nitrogen atom and four hydrogen atoms.

In the NH4+ Lewis structure, there are four single bonds around the nitrogen atom, with four hydrogen atoms attached to it, and none of the atoms has a lone pair.

Also, there is a positive (+1) charge on the nitrogen atom.

Contents

## Steps

Here’s how you can easily draw the NH4+ Lewis structure step by step:

#1 Draw a rough skeleton structure
#2 Mention lone pairs on the atoms
#3 If needed, mention formal charges on the atoms

Now, let’s take a closer look at each step mentioned above.

### #1 Draw a rough skeleton structure

• First, determine the total number of valence electrons

In the periodic table, nitrogen lies in group 15, and hydrogen lies in group 1.

Hence, nitrogen has five valence electrons and hydrogen has one valence electron.

Since NH4+ has one nitrogen atom and four hydrogen atoms, so…

Valence electrons of one nitrogen atom = 5 × 1 = 5
Valence electrons of four hydrogen atoms = 1 × 4 = 4

Now the NH4+ has a positive (+1) charge, so we have to subtract one electron.

So the total valence electrons = 5 + 4 – 1 = 8

• Second, find the total electron pairs

We have a total of 8 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 = 8 ÷ 2 = 4

• Third, determine the central atom

Here hydrogen can not be the central atom. Because the central atom is bonded with at least two other atoms, and hydrogen has only one electron in its last shell, so it can not make more than one bond.

Hence, here we have to assume that the central atom is nitrogen.

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

• And finally, draw the rough sketch

### #2 Mention lone pairs on the atoms

Here, we have a total of 4 electron pairs. And four N — H bonds are already marked. So we do not have to mark any electron pair as a lone pair on the sketch.

### #3 If needed, mention formal charges on the atoms

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 – 0 – ½ (8) = +1

For each hydrogen atom, formal charge = 1 – 0 – ½ (2) = 0

Here, the nitrogen atom has a charge, so mark it on the sketch as follows: