Answer: Magnesium and Bromine/MgBr2 = Ionic compounds
Explanation: When atoms form together they can form between Ionic Compounds and molecules; this could depend on if they're joined by Covalent bonds as well because when atoms form with Covalent bonds, it forms Molecules.
Periodic table is a scientific model
The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of every atom of that element.