How many helium atoms are there in a helium blimp containing 532 kg of helium?

The answer to your question is: 8.01 x 10²⁵ atoms of helium

Explanation:

Data

Helium mass = 532 kg

Also from the periodic table:

He atomic mass = 4 gr

Avogrado's number: 6.023 x 10 ²³

Process (rule of three)

                1 mol of helium  4 kg

                x moles of helium  532 kg

x = 532 x 1 / 4 = 133 moles of helium

                1 mol of helium  6.023 x 10²³ atoms

              133 moles of helium            x            atoms of helium

atoms of helium = 133 x  6.023 x 10²³ / 1 = 8.01 x 10²⁵

"the periodic table is arranged in order of atomic number."