Question

the atom with the largest atomic radius in period 4 (row 4) is - kr k fe fe

Explanation:

Atomic radius generally decreases across a period from left - to - right due to increasing nuclear charge pulling electrons closer. Potassium (K) is the first element in Period 4, having the least effective nuclear charge among these options for its outermost electrons, thus the largest atomic radius.

Answer:

B. K