The mass of a hydrogen atom is 1.673x10^-27 kg.
The mass of an H atom was determined through experiments and calculations using the known atomic mass of hydrogen and its atomic structure.
The mass of an H atom is relatively small compared to other atoms. It is the lightest element and has the smallest atomic mass.
The mass of an H atom can change through nuclear reactions, such as fusion or fission, but its mass remains relatively constant in most chemical reactions.
The mass of an H atom is expressed in scientific notation because it is a very small number and is more convenient to write and work with in this format.