There are 8.61 × 10²⁰ atoms in 0.290 g P₂O₅.
Step 1. Convert <em>grams of P₂O₅ to moles of P₂O₅</em>.

Step 2. Convert <em>moles of P₂O₅ to molecules of P₂O₅</em>.


Step 3. Convert <em>molecules of P₂O₅ to atoms</em>.
There are seven atoms in 1 mol P₂O₅.
∴ 
Answer:
Hydrogen is the most explosive element