Question

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

Explanation:

Atomic radius decreases across a period from left to right. Lithium is on the far left of the second period. Neon is on the far right (noble gas, but in period 2). Carbon is in the middle of period 2. Potassium is in period 4. So lithium has the largest atomic radius among the given second - period elements.

Answer:

lithium