I think you take that then convert to moles then covert that to grams
1 mol = 6.02 x 10²³ atoms
*6.02 x 10²³ is Avogadro's number and you will have to use it to solve this.
# grams oxygen = 2.48 x 10²² atoms x 1 mol x 16.00 g O ÷ 6.02 x 10²³ atoms ÷ 1 mol O = 0.659 grams O
