Atomic radius - core charge vs energy level

AI Thread Summary
The discussion centers on the factors influencing atomic size, particularly comparing beryllium and nitrogen. It highlights that beryllium has a smaller atomic radius than lithium due to a greater core charge. However, when comparing nitrogen to beryllium, nitrogen has a higher core charge but occupies the 2p subshell, while beryllium only has electrons in the 2s subshell. This leads to the conclusion that nitrogen has a smaller atomic radius than beryllium, primarily due to its core charge. Additionally, the use of hydrogen-like radial wavefunctions is mentioned as a qualitative tool to understand atomic radius behavior, although caution is advised in applying this concept beyond small atoms. The radial probability distributions for 2s and 2p states are also referenced, indicating that their maximum probabilities are similar, further complicating the comparison of atomic sizes.
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which one is more important in determining the size of an atom?

for example - Berilium has a smaller radius than Lithium because it has a greater core charge, but what about Nitrogen vs Berilium? Nitrogen has a greater core charge, but it has electrons in the 2p subshell whereas Berilium only goes to 2s.

Thanks in advance
 
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Hi ...,

Nitrogen has smaller radius than Berylium because of the core charge.

Hidrogen-like radial wavefunctions, although not valid for this case, can be used to qualitaively examine the behaviour of the radius (only in this little atoms, be carefull with this). If you look at the radial probability of a 2p state the maximum is not at higher radius value than the 2s, they are similar.

This is a 2s hidrogen-like radial probability graphic (for Z=4) and the corresponding contour plot in the xy plane, and the 2p plot for Z=7. Look at the maximums of prob. but don´t forget theese are hidrogen-like functions
 

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