MOtheory - Chemistry 3140: Advanced Inorganic Chemistry...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Click to edit Master subtitle style Chemistry 3140: Advanced Inorganic Chemistry Bonding Theory Version 3.0: Molecular Orbital Theory
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Bonding Theory Version 1.0: Octet Rule and Classic Lewis Structures. Version 1.5: Resonance
Background image of page 2
Bonding Theory Version 2.0 1s 2s 2p Electron Config. Diagram for Oxygen It’s seems nicely set up for forming two bonds, gaining two additional electrons . .. Sure enough, there’s H2O 1s 2s 2p Electron Config. Diagram for Nitrogen It’s seems nicely set up for forming three bonds, gaining three additional electrons . .. Sure enough, there’s NH3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
1s 2s 2p Electron Config. Diagram for Carbon It’s seems nicely set up for forming two bonds, gaining two additional electrons . .. like CH4? Or what about forming the two bonds, and then gaining two more electrons (maybe two more bonds--both to one p orbital) with the bonded atoms 90o apart . .. like CH4?
Background image of page 4
Hybridized Carbon 1s 2sp3 sp3 hybridized carbon NOW it’s nicely set up for forming four bonds, gaining four additional electrons . .. like in CH4. Valence bond theory: when needed, rearrange the atomic orbitals into hybrids , then attach other atoms to form bonds.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Valence bond theory (bonding version 2.0) and even Lewis Structures (bonding version 1.0) have one huge problem however, and it has to do with O2 … Unlike liquid nitrogen, liquid oxygen is magnetic. Technically, it’s paramagnetic … Origin of all magnetism …
Background image of page 6
Atomic or Molecular Orbitals Atomic Orbital: a region in space of maximum probability of finding an electron around one nucleus. These regions have characteristic shapes and are referred to as s, p, and d atomic orbitals. Molecular Orbital: a region in space of maximum probability of finding an electron around two or more nuclei. These regions have characteristic shapes and are referred to as σ, π, and δ molecular orbitals.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
MO’s, simply put, are linear combinations of atomic orbitals. Using some of the language of quantum mechanics: MO b b a a c c Ψ = Ψ ± Ψ Atomic orbital wave functions Molecular orbital wave function— a new region in space between atoms a and b where electrons may exist Simple diatomic molecule: H A--HB
Background image of page 8
Probability Probability function for Atom A Probability fn. for Atom B For the pchemists out there, recall from quantum mechanics that the square of a wavefunction gives the probability function: 2 2 2 2 2 2 MO b b b a b a a a c c c c Ψ = Ψ + Ψ Ψ + Ψ Here’s the critical one: the overlap … Probability of finding the electrons between atoms A and B MO b b a a c c Ψ = Ψ ± Ψ What’s the plus/minus doing there?
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
A bit more QM Also from quantum mechanics, the actual probability of finding an electron is the integral of the probability function over all space. Written mathematically: Probability function for Atom A: τ d c a a Ψ 2 2 Integrating over all space: Consider Atom B and note that, since the molecule is H2: d c d c b b a a Ψ = Ψ 2 2 2 2
Background image of page 10
Normalized Wavefunctions In the language of quantum mechanics, the wavefunctions to describe electron positions are normalized, meaning that the probability of finding an electron somewhere in the universe is exactly 1.
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 48

MOtheory - Chemistry 3140: Advanced Inorganic Chemistry...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online