Formal Charge?

Question

Wat is the Overall charge of (ClO4)^(-1). Also wat is the Formal oxidation number and Formal charge of Clorine?

Thank you

Answer 1

The overall charge is the number that is at the top right-hand side, in this case it is -1.
To find the oxidation number of Cl... Let's assume it is x. Then the sum of all the oxidation numbers of all the atoms in this group must be equal to the overall charge. Oxygen has usually oxidation number -2 , so we must have
x+4*(-2)= -1 => x-8= -1 => x=+7