Electron configuration homonuclear diatomic

Some heteronuclear diatomic molecules, such as nitric oxide (NO), carbon monoxide (CO) and the short-lived CN molecule, contain atoms which are sufficiently similar that the MOs resemble quite closely those of homonuclear diatomics. In nitric oxide the 15 electrons can be fed into MOs, in the order relevant to O2 and F2, to give the ground configuration... 

Despite its very simple electronic configuration (Is ) hydrogen can, paradoxically, exist in over 50 different forms most of which have been well characterized. This multiplicity of forms arises firstly from the existence of atomic, molecular and ionized species in the gas phase H, H2, H+, H , H2" ", H3+. .., H11 + secondly, from the existence of three isotopes, jH, jH(D) and jH(T), and correspondingly of D, D2, HD, DT, etc. and, finally, from the existence of nuclear spin isomers for the homonuclear diatomic species. 

HOWTO DETERMINE THE ELECTRON CONFIGURATION AND BOND ORDER OF A HOMONUCLEAR DIATOMIC SPECIES... 

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. 

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... 

The electronic configurations of the homonuclear diatomic molecules of the elements of the second period, and some of their ions, are given in Table 4.1. 

Table 4.1 The electronic configurations of some homonuclear diatomic molecules and ions...

Molecular oxygen (or dioxygen) O2 and related species are involved in many chemical reactions. The valence molecular orbitals and electronic configurations of the homonuclear diatomic species O2 and Oj are shown in Fig. 16.1.1. 

Table 6.3. Ground state electron configurations and states for homonuclear diatomic molecules in the first row of the periodic table...

In this section we consider homonuclear diatomic molecules (those composed of two identical atoms) formed by elements in Period 2 of the periodic table. The lithium atom has a 1 s22s electron configuration, and from our discussion in the previous section, it would seem logical to use the Li Is and 2s orbitals to form the MOs of the Li2 molecule. However, the Is orbitals on the lithium atoms are much smaller than the 2s orbitals and therefore do not overlap in space to any appreciable extent (see Fig. 14.33). Thus the two electrons... 

The electron configuration of simple diatomic molecules can be discussed quite simply in terms of the MO s described on p. 84. It is only necessary, in the aufbau approach, to know the energy order of the various orbitals, and for most homonuclear molecules (taking the bond as the z axis) this is ... 

For each of the following valence electron configurations of a homonuclear diatomic molecule or molecular ion, identify the element X, Q, or Z and determine the total bond order. 

Figure 2.3 Electron configurations in first-row homonuclear diatomics originating one-electron (H2 + ), two-electron (H2), three-electron (He2 + ) chemical bonds and Pauli repulsion in He2...

The isoelectronic equivalence is the simplest procedure for estimating electron affinities. It was applied to H2 and I2 and to the atomic electron affinities. Species with the same outer electronic configuration should have similar electron affinities and bond dissociation energies. This results in the relative constancy of the electron affinities of a given family of atoms. The equivalence of the bond dissociation energies for the X2( ) and Rg2(+) ions is also based on this principle. The systematic variation of the electron affinities of the homonuclear diatomic molecules is another example. 

To date, the emphasis has been on the formation of ionic cations or anions, by the formation of inert gas core configurations, which then combine to form purely electrostatic bonds, e.g. Na CP. An alternative type of bond is the covalent bond, which is characterised by the sharing of two electrons by two atoms, in a way that completes the inert gas core of both atoms. Thus, in the case of two hydrogen atoms, both with the same valence shell configuration, ls the formation of a homonuclear diatomic molecule of H2 can be represented, as follows ... 

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