For which one of the following sets of quantum numbers will an electron have the highest energy in a — Atomic Structure Chemistry Question

💡 Solution & Explanation

The energy of an orbital in a multi-electron atom is strictly governed by the $(n+l)$ rule. A higher $(n+l)$ value implies a higher energy level. For option A ($3d$), $n+l = 3+2=5$. For option B ($4d$), $n+l = 4+2=6$. For option C ($4p$), $n+l = 4+1=5$. For option D ($5s$), $n+l = 5+0=5$. Since option B has the highest $(n+l)$ value of $6$, it represents the state of highest energy.