The number 1.00794 in the element square represents what?

The number 1.00794 in the element square represents the Atomic Mass of hydrogen, which is the average mass of its isotopes weighted by their natural abundances. Atomic mass is typically expressed in atomic mass units (amu) and reflects the number of protons and neutrons in the nucleus of an atom. For hydrogen, this value indicates that the average mass of a hydrogen atom is approximately 1.00794 amu.