Core Electrons Show Deeper Effect

In this piece they talk about the ability of Carbon to change its core electron arrangement and the inability of Silicon to follow suit.

It has to do with the Core electrons, those in the already filled shells and orbitals. My dim recall is of the filling order and that outer shell / orbital electrons made for chemical reactions . . . but apparently that’s not the whole story.

Nope, when you think of the structure of the electron arrangement and the type of particles they are it is easy to see how banging, tugging, pushing on one electron has knock-on effects with those electrons in the vicinity. Kind of like tapping on one Bell in a cluster of connected bells.