Which of the following is equal to one mole of calcium atoms?

• A. 40.08 grams of CaCl_2
• B. 6.022 × 10^{23} atoms of Ca
• C. 12.04 × 10^{23} atoms of Ca
• D. 1 gram of Ca

Answer: (B)

Verified step by step guidance

1. Understand that one mole of any element contains Avogadro's number of atoms, which is \$6.022 \times 10^{23}$ atoms.
2. Recognize that the question asks for the quantity equal to one mole of calcium atoms, so we are looking for exactly \$6.022 \times 10^{23}$ calcium atoms.
3. Evaluate each option: 40.08 grams of CaCl\(_2\) is the molar mass of calcium chloride, not calcium atoms alone, so it does not represent one mole of calcium atoms.
4. 12.04 \(\times 10^{23}\) atoms of Ca is twice Avogadro's number, so it represents two moles of calcium atoms, not one mole.
5. 1 gram of Ca is less than the molar mass of calcium (approximately 40.08 g/mol), so it is less than one mole of calcium atoms.