1. Hydrogen Cation (H+)

* This is the most common ion formed by hydrogen.

* It's formed when hydrogen loses its single electron, leaving behind a positively charged proton.

* This ion is extremely reactive and is found in acidic solutions.

2. Hydride Anion (H-)

* This is formed when hydrogen gains an electron to achieve a full outer shell.

* It has a negative charge and is called a hydride ion.

* It's less common than the hydrogen cation but plays an important role in certain chemical reactions.

There are also some rarer, more complex ions that hydrogen can be a part of, like the dihydrogen cation (H2+) and the trihydrogen cation (H3+). However, the H+ and H- are the most important to know for understanding general chemistry.