How do you find the total number of atoms in an equation/formula?

In a copper wire, a temperature increase is the result of which of the following

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.

Draw the lewis dot structure for each of the following polyatomic ions