So, for example, looking at HF and HCl, we see that the 1s orbital of the H overlap with the 2p orbital of F more effectively. Which argument can i use to explain that? Density?
1 Answer
As the quantum number increases, the size of the orbital, or more precisely, the area in which electrons are found, increases. The same 1s orbital of H combines with greater overlap with 2p of F, while the larger 3p of Cl can’t be approached to that extent because of its size. For the sake of demonstration, consider a child shaking hand with the other child, which is a full overlap of palms, while a child shaking hand with an adult is not!
-
$\begingroup$ When I make something bigger, the overlap must increase or stay the same. There are other reasons why the overlap is "less effective". $\endgroup$– Martin - マーチン ♦Commented Mar 15, 2017 at 9:59