Question

what element in the second period has the largest atomic radius?
lithium
carbon
neon
potassium

Explanation:

Atomic radius decreases across a period from left to right. Lithium is on the far left of the second period. Carbon is to the right of lithium. Neon is a noble gas at the end of the second period (but its atomic radius is a van der Waals radius, and among the given options for normal atomic radius comparison in the period (excluding noble - gas radius considerations for a simple left - to - right trend), lithium is larger). Potassium is in the fourth period, so it's not relevant.

Answer:

lithium