Hydrogen atom orbital energy-level diagrams

Molecular Orbitals of H2. The simplest example of a diatomic molecule is H2. For this molecule, the only atomic orbitals available are the Is orbitals of the hydrogens. These orbitals interact to yield bonding als and antibonding als molecular orbitals the molecular orbital energy level diagram is shown in Figure 2-3. (Subscripts are often used to designate the atomic orbitals from which the molecular orbitals are derived.)... 

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. 

Orbital energy-level diagrams for the hydrogen atom and a multielectron atom... 

Figure 3.4 shows a more correctly scaled energy level diagram that results for the hydrogen molecule. Note that the energy for the Is atomic orbital of a hydrogen atom is at — 1312 kJ moT1 because the... 

Figure 9.1. Energy level diagram for hydrogen molecule, H2, and separated atoms H R = 00) and He R = 0). R = the Rydberg constant = 13.6057 eV = 0.5 a.u. (atomic unit of energy). Value from ionization potential of He (Is 2p P). Value from ionization potential of H2. The experimental ionization potentials are quite precise but for systems containing more than one electron their interpretation in terms of orbital energies is an approximation.

Note that all the superscripts for an atom must add up to the total number of electrons in the atom—1 for hydrogen, 3 for lithium, 11 for sodium, and so forth. Also note that the orbitals are not always listed in order of principal quantum number. The 4s orbital, for example, is lower in energy than the 3 dorbitals, as is indicated on the energy-level diagram of Figure 5-22. The 4s orbital, therefore, appears before the 3dorbitaI. 

Figure 1.5 The energy-level diagram for the interaction of

The combination of the atomic Is orbitals to give the two new molecular orbitals is simply shown on an energy level diagram. With one electron in each Is orbital, two hydrogen atoms combine to give a hydrogen molecule. 

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