No individual atom in the sample of 1 mole of Neon has a mass of 20.18 a.m.u. because it is ______?

It is molar mass of Ne

Average atomic mass of Ne

Overall mass of an isobar

It is a fractional mass

The mass of 20.18 a.m.u. is the average atomic mass of Neon, reflecting the weighted average of all its isotopes.

Individual atoms may have slightly different masses due to the presence of isotopes.