What element in the second period has the largest atomic radius?

1 Answer
Mar 17, 2016

Why, lithium.

Explanation:

We look at Li, Z=3, versus Ne, Z=10.

As scientists we should always consider the data . The atomic radius of Li = 167xx10^-12 m; the atomic radius of Ne = 38xx10^-12 m.

This is quite a stunning decrease in radius. Atomic radii decrease ACROSS the Period going from left to right due to increased NUCLEAR CHARGE. As Z increases sequentially, the effective nuclear charge increases as the electrons, adding to the same shell, shield each other VERY imperfectly, and atomic radii contract.