How many grams does an atom of hydrogen weigh?

The weight of an atom is typically expressed in atomic mass units (amu) or unified atomic mass units (u), rather than grams. An atom's weight is extremely small, and using grams as a unit would result in inconveniently large numbers.

The atomic mass of hydrogen is approximately 1.00784 atomic mass units (u) or 1.007825 amu. This value takes into account the mass of the proton and electron in a hydrogen atom. Keep in mind that the atomic mass of an element is the weighted average of the masses of its various isotopes, and hydrogen has different isotopes with slightly different masses.

If you were to convert the atomic mass of hydrogen into grams, it would be an extremely tiny value, roughly 1.673 x 10^-24 grams. This illustrates why atomic masses are typically expressed in atomic mass units, as these units are more convenient for describing the masses of individual atoms.