How do you use the periodic table to determine ION charge?

It is really simple. For the groups 1A and 2A, the charges will be +1 and +2 respectively. For example, Na (sodium) is in group 1, therefore it has a charge of (Na)+ . Ca (calcium) is in group 2, therefore it has a charge of (Ca)+2 .

The groups that have a B after the number are called transition metals because they form cations with various charges. For the metals in group 3A (Aluminum, Gallium and Indium will have 3+ charge). However, Thallium, which is in the same group can have different charges of (+1 and +3).

Now for the NON metals from groups 4A to 7A is easy to predict the charge because the elements in group 8A are called noble gases, which do NOT have charge, they are inert. The elements in group 7A will have -1 charge, the elements in group 6A will have -2 charge, the elements in group 5 will have -3 charge, the elements 4A will have -4 charge.

REMEMBER THAT THIS ONLY APPLIES FOR NON METALS.