Answer:
2.49×10²⁰ atoms of Pb
Explanation:
This a problen that can be solved with a rule of three:
1 atom of Pb weighs 3.44×10⁻²² g
Let's convert the mass from mg to g → 85.9 mg . 1g / 1000mg = 0.0859 g
Now, the rule of three:
3.44×10⁻²² g is the weight for 1 atom
0.0859 g is the weight for ( 0.0859 g . 1) / 3.44×10⁻²² g = 2.49×10²⁰ atoms of Pb
