Electrostatic Effects and Energy Level Splitting

[tortoise11]

Textbook: "Chemistry" by Silberberg. 5th Edition. Page 306

"Electrostatic effects play a major role in determining the energy states of many-electron atoms."

Can someone help me understand this statement? "Electrostatic effects" is not in the textbook glossary, and I'm not having luck on Wikipedia or Google.

Thanks in advance!

 

[Yanick]

Electrostatic interactions refer to the repulsion/attraction forces of charges (whether they be ions, or dipoles, positive nuclear charges interacting with the electron shells or something I haven't even learned of yet).