Energy electron configurations

Because the low-energy electronic configurations of d-block elements and their +1 ions are invariably of sdm form (see Table 2.2, Section 2.8), it is clear that both s and d orbitals will be involved in bond formation at transition-metal centers. What is less clear, a priori, is what role the valence p orbitals will play in bonding of the d-block elements. 

Lowest energy electronic configuration (Electronic ground state)... 

In the H2 molecule the lowest energy electron configuration is obtained by placing both electrons in the aR s molecular orbital with their spins paired so as to satisfy the Pauli exclusion principle. The Slater determinant for this arrangement is... 

In chapter 6 we described the low-lying electronic states of the 02 molecule. In terms of molecular orbital theory the lowest energy electron configuration may be written... 

The first row of transition elements, with their lowest energy electron configurations, are as follows. 

The lowest energy electron configuration of 02, which contains two electrons in it orbitals, gives rise to three states, Table 11-2. 

Replacement of the methylene group in cyclopropyne by oxygen leads to changes in electronic structure similar to those already noted for aziridinediylidene (72). The lowest energy electronic configuration has only two 7t-electrons and corresponds to the dicarbene oxiranediylidene (16) rather than the triply bonded species (which would have four sr-electrons). There is then transfer of t-electrons from oxygen to the formally vacant 2pn orbitals on the carbene centers. In the STO-3G structure, C2 symmetry was assumed and this jt-electron donation (and associated partial double bond character) is reflected in short C—O bonds (1.361 A). Oxiranediylidene is isomeric with ketenylidene ( C=C=0) and is found to be 51.4 kcal/mol less stable than the latter (4-31G). >... 

These bands are related to the four transitions, HOMO-LUMO, next-HOMO-LUMO, HOMO-next-LUMO, and next-HOMO-next-LUMO. The electron configurations of next-HOMO-LUMO and HOMO-next-LUMO are degenerate, and they split into two components by the Cl procedure, one of which lies below the transition of HOMO-LUMO with the lowest energy electron configuration. Therefore the lowest excited state (a band) is one component of the doublet pair (next-HOMO-LUMO and HOMO-next-LUMO). The second band (p band) corresponds to the transition of HOMO-LUMO. The third shortest wavelength and the strongest band (/3 band) is associated with the next HOMO-next-LUMO transition and another component of the doublet pair. 

Ground state (Section 1.3) The most stable, lowest-energy electron configuration of a molecule or atom. 

There is a second possibility. Promotion of an electron from a 2s to a vacant 2p orbital would form four unpaired electrons for bonding. This process requires energy because it moves an electron to a higher energy orbital. This higher energy electron configuration is called an electronically excited state. 

Helium Helium has two electrons, which will fill the lowest energy level. The ground state (lowest energy) electron configuration for helium is Is. ... 

Each element has a specific number of electrons located in an orbital structure that is unique to each element. The lowest energy electronic configuration of an atom is called... 

In this case the orbital correlation diagram shows that the lowest energy electron configuration in the reactant, (711) (712) (713), correlates directly with the lowest energy... 

Understand how the atomic properties (such as ionization energy, electron configuration, and electron affinity) of group 6A, 7A, and 8A elements are related to their chemical reactivity and physical properties. (Section 7.8)... 

The lowest-energy electron configuration for an atom or a molecule. 

List the two lowest-energy electron configurations of atomic beryllium, and give the term states for each, including / values. 

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