To calculate the formal charge of the sulfur atom in the sulfite ion SO3 , we will use the formula for formal charge calculation:Formal charge = Valence electrons of the atom - Non-bonding electrons - 0.5 * Bonding electrons In the case of the sulfite ion, the sulfur atom is bonded to three oxygen atoms, and each bond is a double bond. Sulfur belongs to Group 6 in the periodic table, so it has 6 valence electrons.Non-bonding electrons: Since all three oxygen atoms are double bonded to the sulfur atom, there are no lone pairs on the sulfur atom. Therefore, the number of non-bonding electrons is 0.Bonding electrons: Each double bond consists of 2 pairs of electrons, so there are 2 * 3 = 6 bonding electrons involved in the double bonds.Now, we can plug these values into the formula:Formal charge of S = 6 - 0 - 0.5 * 6 Formal charge of S = 6 - 0 - 3Formal charge of S = 3So, the formal charge of the sulfur atom in the sulfite ion SO3 is +3.