Hydrogen ion
Charge: 1+ · Type: Cation · Molar mass: 1.008 g/mol
Made of: hydrogen
How it forms
A hydrogen atom consists of one proton and one electron. Removing the electron leaves a bare proton, H+. In water this proton immediately attaches to a water molecule to form the hydronium ion, H3O+.
Naming note
H+ is called the hydrogen ion or, in the context of acids, simply a proton. In aqueous chemistry it is usually written as H3O+ (hydronium) to show it is hydrated.
Examples in compounds
Hydrochloric acid
Sulfuric acid
Nitric acid