'Hydrogen' is the first element on the periodic table and is represented by the letter H. it has an Atomic Number of 1 and Atomic Weight of 1 It is a colorless gas at room temperature. To test for it you can use a lighted splint and it will go pop if Hydrogen is present, this is because the Hydrogen reacts with the oxygen to form water.

All acids have hydrogen in them: in water this forms the hydrogen ion (H+). This is also a proton.