Give two differences between magnesium ions and magnesium atoms.

Hint:Magnesium $\left( {Mg} \right)$ lies in group $2$ (alkaline earth metal) and period and a member of s block. Atomic number of magnesium is $12$. Magnesium atoms have $12$ electrons while magnesium ions have $10$ electrons.

Complete step by step answer:

State of magnesium at $20^\circ {\rm{C}}$ is shiny gray solid. Magnesium is the ninth most abundant element found in the universe and eight most abundant in the earth’s crust. It doesn’t occur as a free element, always occurs naturally only in combination with other elements and further artificially free elements or metal is produced.
Magnesium reacts with water at room temperature though the reaction is very slow as compared to the calcium (the element of the same group). When exposed to air it is slightly discolored or tarnished. But it can be stored in an oxygen environment as it is protected by a thin oxide layer which is difficult to remove and impermeable. It is highly flammable when present in powder form or thin strips form although it is difficult to ignite it when present in a mass bulk.
$Mg$ is an atom of magnesium element. It is electrically neutral and has two electrons in its outermost or valence shell.
$M{g^{ + 2}}$ is an ion of magnesium atom which has lost 2 electrons from its valence shell and has attained an electronic configuration of noble gas that is Neon and hence become positively charged.
Electronic configuration of Magnesium $\left( {z = 12} \right)$ is :
$1{s^2}2{s^2}2{p^6}3{s^2}$
Electronic configuration of Magnesium ion,
$1{s^2}2{s^2}2{p^6}$ which is the electronic configuration of Neon.
It depicts that when magnesium loses two electrons it attains the electronic configuration of noble gas that is Neon.
Electronic configuration of Magnesium ion is also written as:
$[Ne]\;3{s^2}$

Note:
Magnesium \[Mg\] or magnesium ion .\[M{g^{ + 2}}\], belongs to the class of inorganic compounds known as homogenous alkaline earth metal compounds.
These are inorganic compounds containing only metal atoms, with the largest atom being an alkaline earth metal atom.