Question

Provide an example of a homodiatomic molecule's MO diagram in which the physical characteristics of the molecule would change based on whether or not the molecule possessed mixed orbitals. List three ways in which a chemist could determine whether or not the molecule has mixed orbitals, and briefly explain how the technique works.

Answer 1

m actually para magnet to the magnet MOT [Hind & Mulliken in 1932 ] Majose Drawbacks of VBT: if In Valence Bond Theory, O2 is supposed to be diamagnetic in nature , but on molecule is A para magnetic. In liquid form it is strongly att react 7 It fails to explain the odd electron bonds in molecules Explaple: Stability of the t , Hat ete cannot be explained. the color de spectra of co-oedination. It cannot explain As an MOs Different energy lenels LLAO OW Linear Combination of Alonic Orbital! In the molecue , molecular orbitals can be regarded as a linear combination of individual atomic orbitals, The combination between the Ao's will be effective if it follows the 3 conditions -

important aspects of Leao! * No. of molecular onbitals are equal to the number of starting atomic orbitale. For an effective combination of Aos , they must satisfy Eos condition. - Depending upon the type of overlap , the molecular oxboitals are classified as bonding, antibonding and non-bonding. Electron density in a BMO is located between the nuclei of the bonded atoms because of which the repulsion between the nuclei is nory less while in case of an antibanding molecular arbital, mosh of the electeron density is located away from the space between the nuclei, hence the gepulsion between the nuclei is high. For simple di-atomic noleate the bond order is calculated as: BO= No. of es in BMO- no. of es in ABMO 2

Het formation is possible. Explain? In the excited state of He molecule , one of electron from la of Is is bocomoted to 46 of.. 25. This bond order becomes s pleng this condition Het is possible, BO= 3-1 = 1 Simple Mo diagram i Limitations! 2p. la O Bo is diamagnetie aceto simple Mo theody, but actually it is peramagnetic O C2 is para magnetic aceto simple Mo, but actually in s 1: Is diamagnet 1. O HOMO of Nz is I from simple Mo theory, but actually it is.r. requirement of So this indicates the modification. order of Mos for biz to F2 : Varciation of energy 21E I II I TI B C N ti Be O F -

Since energy gap between 20 s 2e becon quite large for D₂ z F2 there symmetall interactions is not applicable But for Lięto N₂ the energy gap between 25 22 are comparitinely lower Hence symmeter interaction between the mos is prominent as shown in the diagram . Consequently the lower energy level gets louder down more wheras the higher one is graised more [ Non-Crossing eule (auantum Mechanics) is applicable 2 8F21 Mo diagrams for 2p. A og it ou 2s 47 og 0

e Mo diagrams of N (Courminderen en met sy non-coussing gule) -18 u 25 25