Here's how to break it down:

* NH₄⁺: Ammonium ion

* BrO₄⁻: Perbromate ion

The ammonium ion (NH₄⁺) has a +1 charge, and the perbromate ion (BrO₄⁻) has a -1 charge. These charges balance each other out, resulting in the neutral compound NH₄BrO₄.