Question

The incorrect decreasing order of atomic radii is:

• A. Mg>Al>C>O
• B. Al>B>N>F
• C. Be>Mg>Al>Si
• D. Si>P>Cl>F

Hint:

Remember, atomic radius decreases across periods and increases down groups in the periodic table.

Answer 1

The Correct Option is C

Atomic radius diminishes from left to right across a period because of a heightened effective nuclear charge. Conversely, it expands down a group owing to the inclusion of additional electron shells.

Step 1: \( \text{Be} > \text{Mg} > \text{Al} > \text{Si} \) is erroneous, as atomic radius decreases from \( \text{Be} \) to \( \text{Si} \).

Final Conclusion: The incorrect sequence is presented in Option (3), \( \text{Be} > \text{Mg} > \text{Al} > \text{Si} \).