The number of π molecular orbitals in a molecule is always equal to the number of ________.

A) π bonds
B) p orbitals used to construct the π bonds
C) electrons in the π system
D) hydrogen atoms in the molecule

The number of π molecular orbitals is equal to the number of p orbitals used to construct the π bonds. Each p orbital can form one half of a π bond, so the number of π bonds is equal to the number of p orbitals. However, each π bond involves two electrons, so the number of electrons in the π system is twice the number of π bonds. The number of hydrogen atoms in the molecule is not directly related to the number of π molecular orbitals.