Question

the 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 increases energy.
b) larger nuclear charge lowers energy; more electrons in an orbital lowers energy.
c) smaller nuclear charge lowers energy; more electrons in an orbital increases energy.
d) smaller nuclear charge lowers energy; more electrons in an orbital lowers energy.
e) none of these statements is generally correct.

Explanation:

• Option A: Larger nuclear charge lowers energy (due to stronger attraction between nucleus and electrons), but more electrons in an orbital increase electron - electron repulsion (which raises energy, not lowers). So, this option is incorrect.
• Option B: Larger nuclear charge lowers energy (correct as more protons attract electrons more strongly). More electrons in an orbital lower energy (incorrect, because electron - electron repulsions increase with more electrons in an orbital).
• Option C: Smaller nuclear charge lowers energy (incorrect, smaller nuclear charge means less attraction, higher energy). More electrons in an orbital increases energy (correct due to electron - electron repulsions).
• Option D: Smaller nuclear charge lowers energy (incorrect). More electrons in an orbital lowers energy (incorrect).

Answer:

E. None of these statements is generally correct.