Question

Which group elements have the smallest atomic radii in their respective periods?

• A. group 15
• B. group 16
• C. group 17
• D. group 18

Hint:

Atomic radius shrinks across a period as nuclear charge rises, and the halogens have the smallest radii before the noble gases.

Answer 1

The Correct Option is C

Step 1: Trend.
Across a period, $Z_{eff}$ goes up and radius goes down.

Step 2: Pick.
Group 17 is the last group with a covalent radius before the noble gases. The noble gas radius quoted is the larger van der Waals radius.

Final Answer:
Option (C). \[ \boxed{\text{Group 17}} \]