Answer: The charge of nonmetal ions formed from groups 5, 6 and 7 will be equal to the group number minus 8.
Explanation: The charge on an element is defined as the number of electrons gained or lost by that particular element.
Groups of non-metals are Group 5, Group 6 and Group 7.
Charge on Group 5 = (5 - 8) = -3
Charge on Group 6 = (6 - 8) = -2
Charge on Group 7 = (7 - 8) = -1