Question

Which has a greater number of atoms a gram of helium or a gram of neon?

Answer 1

1 g of He contains greater number of atoms.

Proof:

Number of Atoms in 1 g of He:

Step 1: Calculate Moles of 1 g He as,

Moles = Mass ÷ M.Mass

Moles = 1 g ÷ 4 g.mol⁻¹

Moles = 0.25 mol

Step 2: Calculate Number of Atoms of He as,

# of Atoms = Moles × 6.022 × 10²³

Putting value of moles,

# of Atoms = 0.25 × 6.022 × 10²³

# of Atoms = 1.50 × 10²³ Atoms of He

--------------------------------------------------------------------------------------------------------

Number of Atoms in 1 g of Ne:

Step 1: Calculate Moles of 1 g He as,

Moles = Mass ÷ M.Mass

Moles = 1 g ÷ 20.18 g.mol⁻¹

Moles = 0.0495 mol

Step 2: Calculate Number of Atoms of Ne as,

# of Atoms = Moles × 6.022 × 10²³

Putting value of moles,

# of Atoms = 0.0495 × 6.022 × 10²³

# of Atoms = 2.98 × 10²² Atoms of Ne