How many mole of Bi atoms are needed to combine with 1.58 O atoms to make Bi2O3?
I assume you meant how many moles of bismuth are needed to react with
Well, here's the balanced chemical equation for your reaction
Notice that the balanced chemical equation has 4 moles of bismuth reacting with 3 moles of oxygen to form 2 moles of bismuth (III) oxide.
What that means is that you have a
If you're interested in how many actual atoms of bismuth you'd need, use Avogadro's number to go from moles to atoms