Question

$K$ has a larger atomic radius than $Li$. This confirms:

• A. atomic radius decreases down a group.
• B. atomic radius increases down a group.
• C. atomic radius decreases across a period.
  
• D. atomic radius increases across a period.
  

Answer 1

The correct option is B atomic radius increases down a group.

Atomic radius increases down a group. $K$ and $Li$ are in the same group, and $K$ lies below $Li$. $K$ has a larger atomic radius than $Li$.