Ionization energy successive values

It is possible to remove two or more electrons from a many-electron atom. Of course it is always harder to remove the second electron than the first because the second electron to come off leaves an ion with a double positive charge instead of a single positive charge. This gives an additional electrical attraction. Even so, the values of successive ionization energies have great interest to the chemist. 

Why do the values of successive ionization energies of an atom always show an increasing trend ... 

The MS-A"a method has been very successful for the calculation of ionization energies for both gas-phase molecules and molecular cluster models of solids. DeAlti et al. (1982) have employed both the MS-Aa method and the LCAO-Aa scheme of Sambe and Felton (1975) in the transition-state procedure for calculating ionization potentials for a number of molecules where the Koopmans approximation within Hartree-Fock theory gives the wrong ordering. They found that the LCAO-Aa ionization potentials were more accurate than the Hartree-Fock Koopmans values, while the MS-Aa results typically showed errors of one or two electron volts. Representative results are given for ozone (O3) in Table 3.8. 

Trends within periods As shown in Figure 6-16 and by the values in Table 6-2, first ionization energies generally increase as you move left-to-right across a period. The increased nuclear charge of each successive element produces an increased hold on the valence electrons. 

Our simple model for shows that the trend in successive ionization energies in a single atom arises naturally from screening and shielding. The key idea here is that the higher the value of Z ff, the more energy is required to remove an electron from the atom. In Chapter 5 we combine this simple physical model with principles of quantum mechanics to understand why the electrons are organized in... 

TABLE 7.2 Successive Values of Ionization Energies,/, for the Elements Sodium through Argon (kJ/mol)... 

Scan the successive ionization energies for each element to find a point where removing one additional electron causes a dramatic increase in the value. It is not likely that sufficient energy would be available to compensate for such a large increase in ionization energy, so the ion formed will be dictated by the number of electrons lost before that jump in ionization energy. 

The energy terms associated with the successive ionizations of the neon atom are given in Table 4.2 using the same approximations as those used to explain the pattern of first ionization energies for the atoms from Li to Ne. The values of and increase considerably in magnitude as increases to produce the observed variations. 

I he data below consist of successive ionization energies (in kJ mol ) for three elements. Identify the group of the Periodic Table to which each element belongs, and explain the variations in the values for each element. 

The general variability of the oxidation states of the transition elements is explicable in terms of the closeness of values of successive ionization energies and, for any coordination number, the existence of odd numbers of anti-bonding electrons is not unusual. Such anti-bonding electrons possess almost the same energies that they do in the isolated oxidation state, and do not destabilize the systems sufficiently to rule out their existence. In the latter halves of the transition series, successive ionization energies increase and the attainment of hi er oxidation states is less apparent. 

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