The proton in chemistry-Hydrogen as proton

Since the atomic number of hydrogen is 1, a positive hydrogen ion (H⁺) has no electrons and corresponds to a bare nucleus with 1 proton (and 0 neutrons for the most abundant isotope 11H). In chemistry and biology therefore, the word "proton" is commonly used as a synonym for hydrogen ion (H⁺) or hydrogen nucleus in several contexts:

1. The transfer of H⁺ in an acid-base reaction is referred to "proton transfer". The acid is referred to as a proton donor and the base as a proton acceptor.
2. The hydronium ion (H₃O⁺) in aqueous solution corresponds to a hydrated hydrogen ion. Often the water molecule is ignored and the ion written as simply H⁺(aq) or just H⁺, and referred to as a "proton". This is the usual meaning in biochemistry, as in the term proton pump which refers to a protein or enzyme which controls the movement of H⁺ ions across cell membranes.
3. Proton NMR refers to the observation of hydrogen nuclei in (mostly organic) molecules by nuclear magnetic resonance. This method uses the spin of the proton, which has the value one-half.