Final answer:
Strontium, a group 2 element on the periodic table, typically forms a 2+ ion, denoted as Sr2+. This charge results from losing two valence electrons.
Step-by-step explanation:
The charge of the ion typically formed by strontium is 2+. Strontium belongs to group 2 of the periodic table, which includes the alkaline earth metals. Elements in this group have two valence electrons that they tend to lose when forming ions, resulting in ions with a 2+ charge. Therefore, when strontium forms an ion, it loses two electrons and becomes a Sr2+ ion. This 2+ charge is consistent with the general trend for main-group elements, where they form cations with a charge equal to their group number. It's important to note that while main-group elements generally follow this trend, transition metals may exhibit variable charges that are not predictable solely by their location on the periodic table.