What is the atomic radius of magnesium? — Solid State Chemistry Question

💡 Solution & Explanation

Volume of HCP $= 24\sqrt{2} r^3 = 8 \times 3\sqrt{2} r^3 = 1.25 \times 10^{-22} \text{ cm}^3$. Substituting $3\sqrt{2} = (1.6)^3$, $8 \times (1.6)^3 r^3 = 125 \times 10^{-24} \implies 2 \times 1.6 \times r = 5 \times 10^{-8} \implies r = 5/3.2 \times 10^{-8} \text{ cm} \approx 1.56$ Å. Therefore, correct answer is B.