Here's why:
* Strontium (Sr) is an alkaline earth metal in group 2 of the periodic table. It has a +2 charge when it forms ions.
* Bromine (Br) is a halogen in group 17 of the periodic table. It has a -1 charge when it forms ions.
To form a neutral compound, we need two bromide ions (Br⁻) to balance the +2 charge of the strontium ion (Sr²⁺). This leads to the formula SrBr₂.
