What is the total number of atoms contained in a 1.00-mole sample of helium (He)?

• A. 1.00 × 10^{24} atoms
• B. 3.011 × 10^{23} atoms
• C. 6.022 × 10^{23} atoms
• D. 2.00 × 10^{23} atoms

Answer: (C)

Verified step by step guidance

1. Recall that one mole of any substance contains Avogadro's number of particles, which is approximately \$6.022 \times 10^{23}$ particles per mole.
2. Since helium (He) is a noble gas and exists as individual atoms (not molecules), one mole of helium contains exactly one mole of helium atoms.
3. Therefore, the total number of atoms in a 1.00-mole sample of helium is equal to Avogadro's number.
4. Write the expression for the total number of atoms as: \(\text{Number of atoms} = 1.00 \text{ mole} \times 6.022 \times 10^{23} \frac{\text{atoms}}{\text{mole}}\).
5. This calculation gives the total number of helium atoms in the sample without any further conversion needed.