Here's why:

* Magnesium (Mg) is a metal and forms a cation with a +2 charge (Mg²⁺).

* Bromine (Br) is a nonmetal and forms an anion with a -1 charge (Br⁻).

* To balance the charges, we need one magnesium ion (Mg²⁺) and two bromide ions (2Br⁻).

* The formula for the compound is therefore MgBr₂.

* The name of the compound is formed by combining the names of the cation and anion, with the anion ending in "-ide".

Therefore, the correct name for the compound MgBr₂ is Magnesium bromide.