Orbital energy level diagrams and

C08-0066. According to Appendix C, each of the following elements has a positive electron affinity. For each one, constmct its valence orbital energy level diagram and use it to explain why the anion is unstable N, Mg, and Zn. 

For each of the following, draw a molecular orbital energy level diagram and give the bond order. Tell whether the species would be more or less stable after gaining an electron, (a) 02+ (b) CN (c) S2 (d) NO (e) Be2+. 

Draw a molecular orbital energy-level diagram and determine the bond order expected for each of the following species (a) Li2 (b) Li2+ (c) Li2 . State... 

Draw a crystal field orbital energy-level diagram, and predict the number of unpaired electrons for each of the following complexes ... 

Describe the bonding in [Mn(CN)g]3-, using both crystal field theory and valence bond theory. Include the appropriate crystal field d orbital energy-level diagram and the valence bond orbital diagram. Which model allows you to predict the number of unpaired electrons How many do you expect ... 

For each of the following, sketch the d orbital energy level diagram and put electrons in the orbitals appropriately. 

IV. Molecular Orbital Energy Level Diagrams and The Third Revolution in Ligand Field Theory... 

Although we have used the hydrogen molecule to illustrate molecular orbital formation, the concept is equally applicable to other molecules. In the H2 molecule we consider only the interaction between Is orbitals with more complex molecules we need to consider additional atomic orbitals as well. Nevertheless, for all s orbitals, the process is the same as for Is orbitals. Thus, the interaction between two 2s or 3 orbitals can be understood in terms of the molecular orbital energy level diagram and the formation of bonding and antibonding molecular orbitals shown in Figure 10.22. 

We can summarize all this information in a molecular orbital energy level diagram, and at the same time put the electrons into the orbitals. We need four electrons—two from the alk-ene n bond and two more for the anion (these were the two in the C—H bond, and they are still there because only a proton, H+, was removed). The four electrons go into the lowest two orbitals, /i and j/2/ leaving /j vacant. Notice too that the energy of two of the electrons is lower than it would have been if they had remained in unconjugated p orbitals conjugation lowers the energy of filled orbitals and makes compounds more stable. 

Be able to draw molecular orbital energy-level diagrams and place elections into them to obtain the bond orders and electron configurations of diatomic molecules using molecular orbital theory. (Sections 9.7 and 9.8)... 

Once you have calculated an ab initio or a semi-empirical wave function via a single point calculation, geometry optimization, molecular dynamics or vibrations, you can plot the electrostatic potential surrounding the molecule, the total electronic density, the spin density, one or more molecular orbitals /i, and the electron densities of individual orbitals You can examine orbital energies and select orbitals for plotting from an orbital energy level diagram. 

Figure 7.14 Molecular orbital energy level diagram for first-row homonuclear diatomic molecules. The 2p, 2py, 2p atomic orbitals are degenerate in an atom and have been separated for convenience. (In O2 and F2 the order of

FIGURE 3.31 Atypical molecular orbital energy-level diagram for the homonuclear diatomic molecules Li2 through N2. Each box represents one molecular orbital and can accommodate up to two electrons. 

Step 2 Use matching valence-shell atomic orbitals to build bonding and antibonding molecular orbitals and draw the resulting molecular orbital energy-level diagram (Figs. 3.31 and 3.32). 

FIGURE 3.33 A typical d molecular orbital energy-level diagram for a heteronuclear diatomic molecule AB the relative contributions of the atomic orbitals to the molecular orbitals are represented by the relative sizes of the spheres and the horizontal position of the boxes. In this case, A is the more electronegative of the two elements. 

The molecular orbital energy-level diagrams of heteronuclear diatomic molecules are much harder to predict qualitatitvely and we have to calculate each one explicitly because the atomic orbitals contribute differently to each one. Figure 3.35 shows the calculated scheme typically found for CO and NO. We can use this diagram to state the electron configuration by using the same procedure as for homonuclear diatomic molecules. 

FIGURE 3.37 The molecular orbital energy-level diagram for methane and the occupation of the orbitals by the eight valence electrons of the atoms. 

FIGURE 3.40 The molecular orbital energy-level diagram for SFf, and the occupation of the orbitals by the 12 valence electrons of the atoms. Note that no antibonding orbitals are occupied and that there is a net bonding interaction even though no d-orbitals are involved. 

Construct and interpret a molecular orbital energy-level diagram for a homonuclear diatomic species (Sections 3.9 and 3.10). 

Draw simple molecular orbital energy-level diagrams to indicate how the bonding in the saline hydrides, such as NaH or KH, differs from that between hydrogen and a light p-block element such as carbon or nitrogen. 

Suggest the form that the orbital energy-level diagram would take for a square planar complex with the ligands in the xy plane, and discuss how the building-up principle applies. Hint The d -orbital has more electron density in the xy plane than the dzx- or d -orbitals but less than the dXJ,-orbital. 

In a nickel-containing enzyme various groups of atoms in the enzyme form a complex with the metal, which was found to be in the +2 oxidation state and to have no unpaired electrons. What is the most probable geometry of the Ni2+ complex (a) octahedral (b) tetrahedral (c) square planar (see Exercise 16.96) Justify your answer by drawing the orbital energy-level diagram of the ion. 

Write the shorthand electron configuration and draw the ground-state orbital energy level diagram for the valence electrons in a sulfur atom. 

C08-0031. Construct an orbital energy level diagram for all orbitals with < 8 and / < 4. Use the periodic table to help determine the correct order of the energy levels. 

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