How many p molecular orbitals are present in 1,3,5,7,9-decapentaene?
A)4
B)5
C)10
D)12

Question

Quizplus · Accepted Answer

For a molecule with n carbon atoms, the number of p molecular orbitals is n-1. In this case, there are 10 carbon atoms, so the number of p molecular orbitals would be 10-1 = 9. However, since the molecule is symmetric, the number of unique p orbitals is half of that, which is 4.5. Since a molecule cannot have a fraction of an orbital, we round up to get 5 unique p orbitals. Therefore, the correct answer is (B) 5.

How Many P Molecular Orbitals Are Present in 1,3,5,7,9-Decapentaene