Which of the following molecular orbitals formed from ns and np atomic orbitals has the lowest energy?
A) $\pi _ { np _ { y } }$
B) $\pi _ { \mathrm { np } _x }$
C) $\pi_{ np_t }$ *
D) $\sigma _ { np _ { x } }$
E) $\sigma _ {np _ { x } }$ *

Question

Quizplus · Accepted Answer

The $\sigma _ { np _ { x } }$ molecular orbital has the lowest energy among the options because sigma ($\sigma$) bonds are generally stronger and more stable due to head-on overlap compared to pi ($\pi$) bonds, which result from side-on overlap. The subscript indicates the orientation, but for sigma bonds formed from p orbitals, the orientation (x, y, or z) does not affect the general rule that sigma bonds are lower in energy than pi bonds.

Which of the Following Molecular Orbitals Formed from Ns and Np