Question

The trend in atomic radii on moving down a group, with reference to the alkali metals in Group-1[I A]

• A. increases
• B. decreases
• C. remain constant
• D. none of these

Answer 1

The correct option is A increases

Moving down a group in the periodic table, the number of electrons and filled electron shells increases, but the number of valence electrons remains the same. The outermost electrons in a group are exposed to the same effective nuclear charge, but electrons are found farther from the nucleus as the number of filled energy shells increases. Therefore, the atomic radii increase.