Which of the following numerical expressions gives the number of atoms in 2.0 g of Ne (neon)?

• A. 2.0 \, \text{g} \times \frac{1 \text{ atom}}{20.18 \text{ g}}
• B. 2.0 \, \text{g} \times \frac{6.022 \times 10^{23} \text{ atoms}}{1 \text{ g}}
• C. 2.0 \, \text{g} \times \frac{1 \text{ mol}}{18.02 \text{ g}} \times 6.022 \times 10^{23} \text{ atoms}
• D. 2.0 \, \text{g} \times \frac{1 \text{ mol}}{20.18 \text{ g}} \times 6.022 \times 10^{23} \text{ atoms}

Answer: (D)

Verified step by step guidance

1. Identify the given information: the mass of neon (Ne) is 2.0 g, and the molar mass of neon is approximately 20.18 g/mol.
2. Recall that to find the number of atoms, you first need to convert the mass of neon to moles using the molar mass. This is done by dividing the mass by the molar mass: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\).
3. Next, use Avogadro's number, \$6.022 \times 10^{23}$ atoms/mol, to convert moles of neon to atoms. Multiply the number of moles by Avogadro's number to get the total number of atoms.
4. Combine these two steps into one numerical expression: \$2.0 \text{ g} \times \frac{1 \text{ mol}}{20.18 \text{ g}} \times 6.022 \times 10^{23} \text{ atoms/mol}$.
5. This expression correctly converts grams of neon to moles and then to atoms, giving the number of atoms in 2.0 g of neon.