Electronic configuration energy diagrams

To date there is no evidence that sodium forms any chloride other than NaCl indeed the electronic theory of valency predicts that Na" and CU, with their noble gas configurations, are likely to be the most stable ionic species. However, since some noble gas atoms can lose electrons to form cations (p. 354) we cannot rely fully on this theory. We therefore need to examine the evidence provided by energetic data. Let us consider the formation of a number of possible ionic compounds and first, the formation of sodium dichloride , NaCl2. The energy diagram for the formation of this hypothetical compound follows the pattern of that for NaCl but an additional endothermic step is added for the second ionisation energy of sodium. The lattice energy is calculated on the assumption that the compound is ionic and that Na is comparable in size with Mg ". The data are summarised below (standard enthalpies in kJ) ... 

The electron configuration or orbital diagram of an atom of an element can be deduced from its position in the periodic table. Beyond that, position in the table can be used to predict (Section 6.8) the relative sizes of atoms and ions (atomic radius, ionic radius) and the relative tendencies of atoms to give up or acquire electrons (ionization energy, electronegativity). 

Turn back to Figure 15-11, the energy level diagram of a many-electron atom, and consider the occupied orbitals of the element potassium. With 19 electrons placed, two at a time, in the orbitals of lowest energy, the electron configuration is... 

Figure 2.14. The molecular orbitals of gas phase carbon monoxide, (a) Energy diagram indicating how the molecular orbitals arise from the combination of atomic orbitals of carbon (C) and oxygen (O). Conventional arrows are used to indicate the spin orientations of electrons in the occupied orbitals. Asterisks denote antibonding molecular orbitals, (b) Spatial distributions of key orbitals involved in the chemisorption of carbon monoxide. Barring indicates empty orbitals.5 (c) Electronic configurations of CO and NO in vacuum as compared to the density of states of a Pt(lll) cluster.11 Reprinted from ref. 11 with permission from Elsevier Science.

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. 

C08-0009. Determine the energy level diagram and shorthand notation for the electron configuration of the fluorine atom. 

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

C08-0057. The ground state of V has lower spin than that of Cr. Construct energy level diagrams for the valence electrons that show how electron configurations account for this difference. 

C08-0102. Draw energy level diagrams that show the ground-state valence electron configurations for Cu ,... 

Draw an energy level diagram and write the d electron configuration of [Pt ( 11)3] CI2. ... 

The two possible electron configurations for a this diagram, P cannot, because P measures electron-electron repulsion, not an orbital energy. 

Fe(NH3)e] " is paramagnetic, but [Co (NH3)g is not. Write the electron configuration for each of these metal complexes and draw energy level diagrams showing which has the higher 4. 

Fig. 4. Energy level diagrams showing possible electronic configurations for positively-charged polaron (a) and bipolaron (b) defects and (c) a schematic bipolaron band model. The negatively-charged polaron would carry three electrons and the bipolaron four. Also shown is the neutral polaron-exciton (d) which would decay to restore the chain structure.

Fig. 13 Qualitative molecular orbital energy level diagram of the dimer d orbitals with the 14 electrons showing the electronic configuration 525 27i47i 4o2 (singlet) and the first excited state 828 2it4it 4a1CT 1 (triplet)...

Textbook discussions of homonuclear diatomic molecules are commonly based on the familiar type of MO energy diagram shown in Fig. 3.28, which underlies the standard MO Aufbau procedure for constructing many-electron molecular configurations (which is analogous to the well-known procedure for atoms). Figure 3.28 purports to represent the energies and compositions of available MOs, which are... 

Figure 6.6 Potential energy diagrams for various electronic configurations...

Be able to write both the energy-level diagram and the electronic configuration of an atom or ion by applying both the Aufbau build-up principle and Hund s rule. 

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