Question

Study the orbital diagrams of two atoms $‘X$ and $Y^{\prime }$. Which subshell will be more stable and why?

• A. $X$, exchange energy is maximum, so is stability
• B. $Y$, exchange energy is maximum, so is stability
• C. $X$, exchange energy is minimum, so stability is maximum
• D. $Y$, exchange energy is minimum, so stability is maximum

Answer 1

Answer: (A)

Element X, have half-filled electronic configuration thus will be more stable than Y. This is due to:
1. Symmetrical distribution of electrons in all degenerated orbitals. This makes a configuration stable.
2. Exchange energy: In atom $X$, all are singly occupied orbital. Thus, the electrons can exchange among all five orbitals and will have high stabilisation due to high exchange energy whereas in element $Y$, only three orbitals have singly occupied electron with same spin and thus can show exchange behaviour/exchange energy less than $X$.