The formula for a compound of li₊ ions and br_ ions is written libr. why can't it be written li₂br? why isn't it written brli?

Group 1 elements have an oxidation charge of +1. They are alkali metals and Li is one of them. For Br it is a halogen and in group 7 so it has an oxidation of -1. If we do the criss cross rule it will ha Li+¹ Br-¹. Put each charges interchangeably on each elements. So the charge of Li will be the subscript of Br and vice versa. Since both have the same charge they will cancel out on the final equation of the compound.

Explanation:

b.false that your answer