what is the differnce between magnesium ion and magnesium atom

Q. Give two differences between magnesium ion and magnesium atom ?

Q. A magnesium ion has a net positive charge while the magnesium atom has __________.

Q. The atomic number of magnesium is 12. How many protons are there in the nucleus of magnesium atom? How many electrons and protons does an ion of magnesium which has a charge of +2 contain.

Q. Question 36
Compute the difference in masses of ${10}^3$ moles each of magnesium atoms and magnesium ions.
(Mass of an electron $=9.1\times {10}^{-31}kg)$