Formal Charge Calculator with steps

How to use a Formal charge calculator?

Before using, Formal charge calculator tool, you must know some basic terms that will help you to understand the concept of a formal charge.

The formula used to calculate formal charge –

⇒ Formal charge = (valence electrons – nonbonding electrons –   1/2 bonding electrons)

Where,

V = Valence electrons (outershell electrons of atom)

N = Non bonding electrons (also called lone pair electrons)

B = Bonding electrons (total electrons shared in bonds with another atom)

Now, in Four steps you can calculate the formal charge for the atoms. To understand that we have to take an example.

Let’s take the example of the NH3 molecule,

This is the lewis structure of NH3, Let’s calculate the formal charge on the Nitrogen (N) atom of it.

Step 1 – Find the valence electron of the nitrogen atom.

The nitrogen atom belongs to the 5A group in the periodic table, hence, the number of valence electrons in the nitrogen atom is 5.

Also read:- 

• How to find valence electrons?

Step 2 – Find the number of nonbonding electrons on the nitrogen atom

Nonbonding electrons also called lone pair electrons are represented as dots in the structure of molecules or atoms. They do not take part in the formation of bonds.

Note: 1 lone pair means 2 nonbonding electrons

So, the number of nonbonding electrons on the Nitrogen atom is 2.

Step 3 – Find the number of bonding electrons around the nitrogen atom

Bonding electrons are the number of electrons shared in bonds with other atoms. They are mostly represented as single, double, or triple bonds in the structure of a molecule.

Note: One single bond contains two bonding electrons.

So, the number of bonding electrons around the Nitrogen atom is 6.

Step 4 – Calculate the formal charge of the nitrogen atom

So, we have got the data for calculating the formal charge for nitrogen atoms.

 For nitrogen atom

⇒ Valence electrons of nitrogen = 5

⇒ Nonbonding electrons on nitrogen = 2

⇒ Bonding electrons around nitrogen (3 single bonds) = 6

Put these values in the Formal charge calculator and hit the calculate button.

Also, check –

• Molecular geometry calculator
• Bond angle calculator

How to calculate the Formal charge for Compounds?

Let’s say you have to find the overall formal charge for the compound. Let’s take an example of a CO2 compound. Before calculating the formal charge for CO2, first, you must draw the lewis structure for CO2.

For instance, the structure of CO2 is –

Let’s find out the formal charge for the individual atom of the CO2 molecule.

Start with an oxygen atom –

⇒ The number of valence electrons in the oxygen atom is 6.

⇒ Nonbonding electrons of oxygen = 4

⇒ Bonding electrons around oxygen (one double bond) = 4

∴ (6 – 4 – 4/2) = 0 formal charge on the oxygen atom.

Now calculate the formal charge for the carbon atoms.

⇒ Valence electrons of carbon = 4

⇒ Nonbonding electrons on carbon = 0

⇒ Bonding electrons around carbon (two double bonds) = 8

∴ (4 – 0 – 8/2) = 0 formal charge on the carbon atom.

So, Each atom (carbon and oxygen) in the CO2 structure gets a formal charge equal to zero.

Therefore, the overall formal charge in CO2 is zero, and according to the concept of formal charge, this is the best and most stable structure of CO2.

So, that’s you can easily calculate the formal charge for any atom or molecule, or you can use our Formal charge calculator tool to get the answer quickly.

Formal charge is very neccessary to check the stability of lewis structures.

Also see, How to draw a lewis structure?

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