[vekete]

I got this question during my exam today and i was so confused what i fid did was was get the number of moles which turned out to be 0.803(100÷31×4) and multiplied it by Avogadro's number. Is this right it turmed out to be smth like 4.45×10^23 or 24

[Borek]

You are asked about atoms, not molecules (so P, not P₄ is what you should base your calculations on).