The charge of the ion here would be +2.
Ions are atoms which have either lost or gained electrons. This makes them become charged.
Each proton has a charge of +1 and each electron is -1
25 protons = +25
23 electrons = -23
Net charge = (+25) + (-23) = -2
You can identify an ion by the number of protons, this is called the atomic number.
Element 25 = Manganese
So the ion you are asking about is
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Hope this helps!