Question

To how many significant figures would you need to express the mass of an hydrogen-1 atom in

amu
to notice the change in mass that occurs when it gains an electron

Answer 1

5 sig figs

Step-by-step explanation:

according to the textbook

Answer 2

Five significant figures

Mass of H-1 atom = 1.0078 u

Mass of electron = 0.0006 u

Total mass = 1.0084 u

You would have to express the mass of a hydrogen atom as 1.0078 u (five significant figures) to notice the change in mass as it gains an electron.