An atom of Al which has 13 protons and 10 electrons is Al cation (Al⁺³)
Explanation:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other.
For example,
Al atom has 13 protons and 13 electrons. The number of positive and negative charge is equal thus it will be neutral atom.
While the atom of Al which have 13 proton and 10 electron is not neutral. The positive charge is greater than negative by 3. Which means 3 electrons are lose by Al atom and form cation "Al⁺³".
Thus an atom of Al which has 13 protons and 10 electrons is Al cation (Al⁺³)
