Formal charge is a way to determine the distribution of electrons in a molecule or ion. To calculate the formal charge of an atom, you can use the following formula:
Formal Charge = Valence Electrons - (Non-bonding Electrons + 0.5 * Bonding Electrons)
Here are the formal charges for hydrogen (H), oxygen (O), and fluorine (F) in different molecules:
Hydrogen (H):
In a molecule like H2, each hydrogen atom shares one electron in a covalent bond.
Formal Charge = 1 (Valence Electrons) - 0 (Non-bonding Electrons) - 0.5 * 2 (Bonding Electrons) = 0
Oxygen (O):
In a molecule like H2O, the central oxygen atom forms two covalent bonds with hydrogen atoms.
Formal Charge = 6 (Valence Electrons) - 2 (Non-bonding Electrons) - 0.5 * 4 (Bonding Electrons) = 6 - 2 - 2 = 2
Fluorine (F):
In a molecule like HF, the fluorine atom forms one covalent bond with hydrogen.
Formal Charge = 7 (Valence Electrons) - 0 (Non-bonding Electrons) - 0.5 * 2 (Bonding Electrons) = 7 - 0 - 1 = 6
The formal charge of oxygen in H2O is +2, while the formal charge of fluorine in HF is +6.
Keep in mind that formal charges are a simplified way to assess electron distribution and are used to help understand the electron configuration in a molecule. They do not necessarily represent the actual charge of the atom.