What is the mass of a single hydrogen atom?

The mass of a single hydrogen atom is approximately 1.6735 x 10^-24 grams. This value stems from the fact that hydrogen, being the lightest and simplest element, has an atomic mass of about 1 atomic mass unit (amu), which is defined as 1/12 the mass of a carbon-12 atom. When converted to grams, this mass corresponds to approximately 1.6735 x 10^-24 g.

To provide context, other values listed for the mass of hydrogen do not accurately reflect the mass of a single atom. For instance, 1.007 g is a reference to the atomic mass in grams per mole and does not represent a single atom. Similarly, 2.016 g corresponds to the molecular mass of molecular hydrogen (H₂), which consists of two hydrogen atoms, and 3.2 x 10^-24 g also exceeds the mass of a single hydrogen atom, increasing the atomic mass inaccurately. Therefore, the choice of 1.6735 x 10^-24 g correctly represents the mass of an individual hydrogen atom.