W2013CHM2311 Part 4b Notes

# 5 ev o 2s 324 ev e 129 ev energy 2s c co 2s o the

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Unformatted text preview: ls Adding Electrons… 2 σ* 2 π* 2 π* 2py 2px 2pz energy - 15.9 eV 1 π 1 π 1 σ 2px 2py 2pz - 18.7 eV 2s - 32.4 eV O Atomic Orbitals 2 n.b. 1 n.b. OF- MOs 2s - 46.4 eV F Atomic Orbitals - MO Descrip0on of OF 1. Bond Order: (6- 4)/2 = 1 (Single Bond) 2. Electron distribu0on in the molecule as a whole is determined by adding all the occupied orbitals together •  Bonding MOs are shived toward F (contain 6 e- ) •  An0bonding MOs are shived toward O (contain 4 e- ) •  Overall, more e- are shived toward F. Conclusion: O- F bond is polarized toward ﬂuorine Compare this model to the model of OF- given by Lewis theory. Derive the MO Diagram of HF ↳  use sketches to illustrate what the MOs might look like 1.  Draw the atomic orbitals and show their rela0ve energies 2.  Determine which orbitals on H can interact with which orbitals on F based on: a) symmetry b) energy 3.  Draw the MOs showing appropriate energies and shapes 4.  Add electrons to the MOs. Note: only the occupied orbitals will inﬂuence the proper0es of the molecule. Derive the MO Diagram of HF Step 1: Show atomic orbitals with appropriate orienta0on and rela0ve energies. x z Energy 1s y 2px 2py 2pz - 13.6 eV - 18.7 eV 2s H HF F - 46.4 eV Derive the MO Diagram of HF Step 2: Orbitals can only interact if their energy separa0on is <13 eV. 5.1 eV Energy 1s - 13.6 eV 2px 2py 2pz 32.8 eV - 18.7 eV 2s H HF F - 46.4 eV Energy & Symmetry Considera0ons The energy gap between H (1s) and F (2s) is too large...
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