Question

1.

a) What is the homo and lumo for formaldehyde? What combinations of atomic orbitals make up the homo and lumo of formaldehyde? (give detailed epxlanation)

b) What is the homo and lumo of Benzene and Butadiene? How many nodes does each m.o contain?

c) What are the changes in shape of both ammonia and BF3 moieties in the complex compared to their corresponding monomer structures?

Answer 1

o formaldehyde Hic=0 HI 1 spa sp² nhybrid firstly o prosbital with 16- H - O sp² Hybridization sp² Hybridised Carbon with unhybrid i p orbital having it These two unhybrid p-orbital ( one from Carbon and one from oxygen) sever are the atomic orbitals for Combination T* Lumo Carbon Toxygen AL TE Homo

Benzene S ago The 6 p-orbitals combine to give six molecular orbitals as shown Below bebe 3 Nop. 6 Nodes N.P. 2 Nop. N.P. 2 Nopu u Nodes 4 Nodex Anti Bonding LUM Tr ル 88 Bonding » HOMO 47 I Nodal 1 Nop. 2 Nodex plane (Nop. ) nu 2 Nodes o Node

Butadiene CH₂=CH-CH=CH₂ - CH CH - CH-CH 0 ² 0 0 0 ² 4 p-orbital Combine to give 4m.o, as shown 0:0!ie - TH 2 3 N. P: 3 Nodes LUMO 2 Nopo 2 Node) Anti bonding I Below so so so. fif ff - II = Bonding 112 - HON Homo 1 Nopo 1 Node BF3 Geometry ? Both are shape – Trigonal Geometry Tetrahedral Shape pyramidal in complexes Both Nhz & Brz are Planar Tetrochetral