Atomic Mass Units
Yes, but we don't normally use those units for measuring the mass of an atom. It's much more convenient to use something called the atomic mass unit, or amu. That's about the mass of one proton or neutron. Many versions of the periodic table (though not ours) give the atomic masses of the elements in amu; these are average masses, taking into account the different isotopes that exist.
One gram is about 600,000,000,000,000,000,000,000 amu (that's 600
sextillion, or a 6 followed by 23 zeros). A pound is just shy of 300
septillion amu--that is, 300,000,000,000,000,000,000,000,000. (26 zeros
Wow--I can see why you'd want to use amu's instead of grams.
If you think about it, what we do today isn't so different from the way
Mendeleev thought of atomic mass. He used the hydrogen atom as a unit--one
oxygen atom has a mass of sixteen hydrogens, and so forth. And the most
common isotope of hydrogen has just one proton and
no neutrons, so one hydrogen atom is about one amu.
What about the mass of the electron in the hydrogen atom?
Electrons are so light that you can usually ignore their mass relative to the
atom as a whole. A proton has about 2000 times the mass of an electron.