When electrons are in only single atom than electrons have interaction with only one nucleus and it nearby atoms. In this situation atom is like isolated. And energy levels of electrons remains unsplited or remains energy level like hydrogen atoms energy levels. But when this atom comes in group of atoms. Than its electrons feels effects of it nucleus and other all surrounding nucleus and electrons. Due to this effect it energy levels does not remain level but become bands.
Get Answers For Free
Most questions answered within 1 hours.