Energy states of atoms containing more than one electron arise from nucleus-electron and electron-electron interactions. Which of the following statements correctly describes these effects?
A) Larger nuclear charge lowers energy, more electrons in an orbital lowers energy.
B) Larger nuclear charge lowers energy, more electrons in an orbital increases energy.
C) Smaller nuclear charge lowers energy, more electrons in an orbital lowers energy.
D) Smaller nuclear charge lowers energy, more electrons in an orbital increases energy.
E) None of the above statements is generally correct.

Question

Quizplus · Accepted Answer

Larger nuclear charge, or higher atomic number, attracts electrons more strongly and therefore lowers their energy. However, having more electrons in an orbital increases electron-electron repulsions, which raises their energy. This effect is known as electron-electron repulsion or electron correlation, and it leads to the splitting of electron energy levels in multi-electron atoms. Therefore, the correct statement is that larger nuclear charge lowers energy, while more electrons in an orbital increase energy.

Energy States of Atoms Containing More Than One Electron Arise