Calculate the number of atoms in 1.004 mol bismuth

1 mole of any substance contains Avogadro's number of atoms.
Therefore, to know the number of atoms in 1.004 moles of Bismuth, all you have to do is multiply the given number of moles by Avogadro's number as follows:
number of atoms = 1.004 * 6.022 * 10^23 = 6.046088 * 10^23 atoms

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer