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.

Alternative method: Lewis structure of NH₄⁺

Rough sketch

• 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

Learn how to find: Nitrogen valence electrons and Hydrogen valence electrons

• 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

Lone pair

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.

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 – 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:

Final structure

The final structure of NH₄⁺ involves a central nitrogen atom connected to four hydrogen atoms through single covalent bonds. Within this layout, the nitrogen atom satisfies the octet rule by forming four bonding pairs. Each hydrogen atom reaches its stable duet state through its shared bond. This arrangement is the most stable because it optimizes the formal charge distribution; the nitrogen atom carries a formal charge of +1, while each hydrogen atom maintains a formal charge of zero. Thus, this specific electronic distribution serves as the definitive and most accurate Lewis representation of the ammonium ion.

To complete the representation, draw square brackets around the entire Lewis structure and place a “+” or “+1” sign as a superscript outside the upper right bracket. This notation signifies that the positive charge is a property of the whole ion.

Next: NH₂^– Lewis structure

External video

• NH4+ Lewis Structure – How to Draw the Dot Structure for NH4+ (Ammonium Ion) – YouTube • Wayne Breslyn

External links

• https://techiescientist.com/nh4-lewis-structure/
• https://www.chemistryscl.com/general/NH4+lewis-structure/index.php
• https://lambdageeks.com/nh4-lewis-structure/
• https://www.thegeoexchange.org/chemistry/bonding/Lewis-Structures/NH4Plus-Lewis-structure.html
• https://lambdageeks.com/ammonium-lewis-structure/