Why is Na the largest radius?

1 Answer
Mar 28, 2018

Na has the largest radius of the atoms in the second shell because it has the fewest protons to produce a positive charge

Explanation:

All the electrons in the second shell are about the same energy level and distance from the nucleus to start out with.

Sodium has only 11 protons to produce the positive charge that will pull the electrons closer to the nucleus. ( the lowest electronegativity of the second shell)

Chlorine has 17 protons to produce the positive charge that will pull the electrons closer to the nucleus. ( The highest electronegativity of the period.) As the electrons start about the same distance from the nucleus a high positive charge will pull the electrons in tighter and closer.