Calculate the mass, in grams, of a single rubidium atom ( mRb = 85.468 amu)?

you just have to divide it by avogadro’s number

because there are 6,023*10^23 atoms of rubidium in one mol and one mol has a mass of 85,468g

and that is 1,419 * 10^ -22

hope it helps 🙂
I assume this is for a chemistry class or something, and are probably expected to determine this using molar mass and avogadro’s number (6.022e23 atoms per mole) 1 mole of gold is 196.97 grams since 196.97 is the molar mass. A mole of anything, has 6.022e23 atoms (for elements) or molecules (for compounds) per 1 mole of whatever substance it is. You have 1 mole of gold. So just divide by how many atoms there are in that 1 mole to find the weight of 1 atom. 196.97/6.022e23