Final answer:
Alpha protons are primary hydrogens attached to a carbon atom with three hydrogens. This terminology is distinct from terms like protium, deuterium, and tritium, which refer to hydrogen isotopes differentiated by their number of neutrons.
Step-by-step explanation:
Primary hydrogens, those on a carbon atom with three hydrogens attached, are called alpha protons. This terminology is derived from the Greek alphabet where alpha is the first letter, indicating the first or primary position next to the carbon in question. A primary hydrogen is therefore attached to a primary carbon, which is a carbon atom bonded to only one other carbon atom. It's important to note that this terminology is separate from the isotopic nature of hydrogen atoms, such as protium, deuterium, and tritium, each defined by the number of neutrons present in the nucleus. Protium, or 1H, is the most common isotope of hydrogen with no neutrons. Deuterium, or 2H, has one neutron, and tritium, or 3H, has two neutrons and is radioactive.