What is the mass of 3.31 × 1024 sulfur atoms?

1) Before we discover the mass of those atoms, it's necessary to discover how many moles are present with those atoms. To do that, we use the Avogadro's number,which is 6,02 x 10²³atoms/mol. In 1 mole there are 6,02 x 10²³ atoms present. So, in 3.31 × 10²⁴ sulfur atoms we have how many moles?

1 mol6,02 x 10²³
x mol 3.31 × 10²⁴
x= 3.31 × 10²⁴ ÷ 6,02 x 10²³
x= 5,498 mol

2) Now we can start calculating the mass.
There is a formula that can give us the mass, if we have the nº of moles and the molar mass. The nº of moles it's already solved(5,498 mol) and for the molar mass we only have to consult the periodic table about the sulfur atoms, which is 32 g /mol
nº of moles= mass/ molar mass
 5,498 mol= mass / 32
mass= 175,94 grams

They are all full and don't need any more electrons in there outer shell.