Energy differences of molecular orbitals

In summary, the conversation discussed the comparison of energy differences between the 1s antibonding orbital and the 2s bonding orbital in molecules A-A and A-B. It was mentioned that antibonding orbitals are generally higher in energy than bonding orbitals, and that MO diagrams can be constructed by following certain rules. This skill is typically taught in inorganic chemistry at universities. However, there was some confusion about the energy levels of the 1s and 2s orbitals, with one person stating that the 1s antibonding orbital has higher energy than the 2s bonding orbital, which was later corrected. The textbook states that for homonuclear diatomic molecules of the first 10 elements, from H
  • #1
Helena Wells
125
9
Suppose we have a molecule A-A and a molecule A-B . And we want to compare the differences in energy of the different molecular orbitals for example the 1s antibonding orbital with the 2s bonding orbital.How can we do that?
 
Last edited:
Chemistry news on Phys.org
  • #2
Antibonding orbitals are higher in energy than bonding orbitals. you can construct MO diagrams by following certain rules. at my university the skill is taught in inorganic chemistry
 
  • Skeptical
Likes Helena Wells
  • #3
docnet said:
Antibonding orbitals are higher in energy than bonding orbitals. you can construct MO diagrams by following certain rules. at my university the skill is taught in inorganic chemistry
I don't think that is true . Are you saying the 1s antibonding orbital has higher energy than the 2s bonding orbital?
 
  • #4
Helena Wells said:
I don't think that is true . Are you saying the 1s antibonding orbital has higher energy than the 2s bonding orbital?
I was mistaken. Now I don't think the question makes any sense.
 
  • #5
Here you go. My textbook says 2s-2s bonding orbitals are higher in energy than the 1s-1s antibonding orbitals for homonuclear diatomiicc molecules of the first 10 elements, from H to Ne.
Screen Shot 2021-02-21 at 5.52.43 PM.png
 

Attachments

  • 2021-02-21 17-50.pdf
    480.3 KB · Views: 212

FAQ: Energy differences of molecular orbitals

What is the concept of energy differences of molecular orbitals?

The energy differences of molecular orbitals refer to the variation in energy levels between different molecular orbitals within a molecule. This concept is important in understanding the stability and reactivity of molecules.

How are the energy differences of molecular orbitals calculated?

The energy differences of molecular orbitals are calculated using quantum mechanical methods, such as the Hartree-Fock method or density functional theory. These methods use mathematical equations to determine the energies of the different molecular orbitals.

What factors influence the energy differences of molecular orbitals?

The energy differences of molecular orbitals are influenced by the types and positions of atoms in a molecule, as well as the electronic interactions between these atoms. The symmetry of the molecule also plays a role in determining the energy levels of its molecular orbitals.

How do energy differences of molecular orbitals affect chemical reactions?

The energy differences of molecular orbitals are crucial in determining the reactivity of a molecule. A larger energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) indicates a more reactive molecule, as it requires less energy to promote an electron from the HOMO to the LUMO in a chemical reaction.

Can energy differences of molecular orbitals be experimentally measured?

Yes, energy differences of molecular orbitals can be measured using spectroscopic techniques such as UV-Vis spectroscopy. These techniques involve shining light of different wavelengths onto a sample and measuring the absorbance or emission of light, which can provide information about the energy levels of the molecular orbitals.

Back
Top