Answer:
Cl < P < Mg < Na
Explanation:
Cl must have the smallest radius because it is located to the right of the remaining elements on the same row. P must have the second smallest radius because it is located to the right of the remaining elements on the same row. Mg must have the Third smallest radius because it is located to the right of Na on the same row. Therefore, Na has the Largest radius.
I hope it helps.
