Question

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

Explanation:

To determine the atom with the largest atomic radius in Period 4, we use the trend of atomic radius in a period: atomic radius generally decreases from left to right across a period. This is because as we move from left to right, the number of protons in the nucleus increases, leading to a greater effective nuclear charge that pulls the electrons closer to the nucleus, reducing the atomic radius. In Period 4, the elements are arranged from left (Group 1) to right (Group 18). Potassium (K) is in Group 1 (the leftmost group in Period 4 among the given options), Iron (Fe) is in the middle - transition metals, and Krypton (Kr) is a noble gas on the right - most part of the period. So, following the left - to - right decrease in atomic radius, K should have the largest atomic radius among K, Fe, and Kr.

Answer:

The atom with the largest atomic radius in Period 4 is K (Potassium). Among the given options (assuming the first Fe is a duplicate and the options are Fe, Fe, Kr, K), the correct one is K. So the answer is the option with "K".