Group 4 dont do Ions.
An ion is an atom which has a different number of electrons from protons or in short words "An ion is a positive or negative type of atom" is the definition of an ion. If you want to find an ion from the periodic table then you need to know some rules:
1. Non metals have 'ite' in the end e.g. sulphur= sulphite
2. Metal ions are just the name of the element e.g. magnesium= magnesium