Question

The two electrons have the following set of quantum numbers:
$P=3,2,-2,+\frac{1}{2}$ $Q=3,0,0,+\frac{1}{2}$
Which of the following statement is true?

• A. $P$ has lesser energy than $Q$
• B. $P$ and $Q$ have same energy
• C. $P$ and $Q$ represent same electron
• D. $P$ has greater energy than $Q$

Answer 1

The correct option is D $P$ has greater energy than $Q$

P has greater energy than Q.
According to Aufbau principal, "in the ground state, the orbitals are filled with electrons in order of increasing energies." Orbitals are filled in order of increasing value of $(n+l)$. If two orbitals have same value of $(n+l)$, then the orbital with lower value of n will be filled first.
For P, $(n+l)=3+2=5$.
For Q, $(n+l)=3+0=3$.