Highest-occupied energy level

One can detennine the total number of electrons in the system by integrating the density of states up to the highest occupied energy level. The energy of the highest occupied state is called the Eermi level or Eermi energy, E ... 

According to the Pauli principle two electrons can adopt the same wave function, so that the N electrons of the N hydrogen atoms take the energy states in the lower half of the band, and the band is said to be half occupied . The highest occupied energy level... 

The spectra of linear polyenes are modelled well as one-dimensional free-electron systems. The cyanine dyes are a classical example. They constitute a class of long chain conjugated systems with an even number n of 7r-electrons distributed over an odd number N = n — 1 of chain atoms. The cyanine absorption of longest wavelength corresponds to promotion of an electron from the highest occupied energy level, En/2 to the lowest unoccupied level, such that in terms of a free-electron model... 

The n value of the highest occupied energy level is the period number. For example, atoms of elements that have electrons with n = 3 appear in period 3. Atoms of elements that have electrons with n = 6 appear in period 6. 

In order to handle the case of a system which is a mixture of pure states corresponding to various numbers of electrons, we must consider such large-r region, where the density is predominantly composed of the contributions due to the orbitals of the highest occupied energy level [see Eqs. (153)-(157)] with the occupations given by (203) because of the decomposition (197). Thus... 

As is shown in Figure 3 the highest occupied energy level is found to parallel well the oxidation potential in aniline and p-phenylenediamine derivatives. To elucidate the existence of the optimum oxidation potentials for antioxidation and antiozonization, the reactivity indices Sr and S for radical and nucleophilic reactions have been used. These are ... 

Figure 3. Relation between the oxidation potential and the highest occupied energy level of amine...

In this expression c is a proportionality factor to exclude the core and n is the principal quantum number that corresponds to the highest occupied energy level of the free atom. Any simulation of interactions in the valence state might begin with this formulation. 

This model qualitatively reproduces the Hiickel m.o. diagram of Fig. 11.1 fori the lowest and highest occupied energy levels. 

Draw general electron structures for the A group elements using the IJk notation, where n is the principal quantum number for the highest occupied energy level. 

Write formulas for two cations that have each of the following electron configurations in their highest occupied energy level (a) hs hp -, (b)... 

Theoretically, any species that contains an unshared electron pair could act as a base. In fact, most ions and molecules that contain unshared electron pairs undergo some reactions by sharing their electron pairs. Conversely, many Lewis acids contain only six electrons in the highest occupied energy level of the central element. They react by accepting a share in an additional pair of electrons. These species are said to have an open sextet. Many compounds of the Group IIIA elements are Lewis acids, as illustrated by the reaction of boron trichloride with ammonia, presented earlier. 

Valence electrons are those in the highest occupied energy level of an atom that are directly involved in the chemistry of the element. Alternatively, they are the electrons outside the noble gas core of the atom. 

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