To determine the formal charge of an atom in a molecule, follow these simple steps:

Understanding Formal Charge
Formal charge is a theoretical charge assigned to an atom in a molecule, which helps in understanding the distribution of electrons and the stability of the molecule. It is calculated using the formula:

Formal Charge Formula
- **Formal Charge (FC) = Valence Electrons - (Non-bonding Electrons + 1/2 Bonding Electrons)**
Where:
- **Valence Electrons** are the electrons in the outermost shell of the atom.
- **Non-bonding Electrons** are the lone pair electrons on the atom.
- **Bonding Electrons** are the electrons shared in bonds with other atoms.

Steps to Calculate Formal Charge
1. **Identify Valence Electrons**: Determine the number of valence electrons for the atom based on its group number in the periodic table.
2. **Count Non-bonding Electrons**: Count the lone pairs of electrons that are present on the atom.
3. **Count Bonding Electrons**: Count the total number of electrons involved in bonds (each bond contributes two electrons).
4. **Apply the Formula**: Plug these values into the formal charge formula to calculate the formal charge.

Interpreting Formal Charge
- A formal charge of **zero** is often ideal for stability.
- Positive and negative formal charges indicate electron deficiency or excess, respectively.
- The sum of formal charges in a neutral molecule should equal zero, while in ions, it should equal the ion’s charge.
By ensuring the correct calculation of formal charge, you can analyze molecular structures and predict reactivity accurately. This understanding is critical in organic and inorganic chemistry.