Question

Which of the following is the correct order of increasing atomic size?

• A. \( \text{Na} < \text{Mg} < \text{Al} \)
• B. \( \text{Na} > \text{Mg} > \text{Al} \)
• C. \( \text{Mg} < \text{Na} < \text{Al} \)
• D. \( \text{Al} < \text{Na} < \text{Mg} \)

Hint:

As you move across a period from left to right, the atomic size decreases due to increasing nuclear charge.

Answer 1

The Correct Option is B

Atomic size decreases as we move from left to right across a period in the periodic table because the effective nuclear charge increases, pulling the electrons closer to the nucleus. Thus, the correct order of increasing atomic size is: \[ \text{Na} > \text{Mg} > \text{Al} \] Thus, the atomic size decreases from sodium (Na) to magnesium (Mg) to aluminum (Al).