Why do some elements have multiple ionic charges? like the transition metal copper, why can it form both cu+ and cu2+ ions?

Ans. : frostbite is when exposure to cold temperatures causes freezing to the skin or other tissues. it most commonly affects the hands, feet, and face. the longer areas are exposed to cold, typically the worse the frostbite. the water temperature used for rewarming a frostbitten part should be : (102 -105) f degrees.

It idk haha what are we doing?