Sodium ionization energies

S = Heat of sublimation of sodium D = Dissociation energy of chlorine / = Ionization energy of sodium = Electron affinity of chlorine Uq = Lattice energy of sodium chloride AHf = Heat of formation of sodium chloride. 

Were we to simply add the ionization energy of sodium (496 kJ/mol) and the electron affin ity of chlorine (—349 kJ/mol) we would conclude that the overall process is endothermic with AH° = +147 kJ/mol The energy liberated by adding an electron to chlorine is msuf ficient to override the energy required to remove an electron from sodium This analysis however fails to consider the force of attraction between the oppositely charged ions Na" and Cl which exceeds 500 kJ/mol and is more than sufficient to make the overall process exothermic Attractive forces between oppositely charged particles are termed electrostatic, or coulombic, attractions and are what we mean by an ionic bond between two atoms... 

ESCA has been used to determine the molecular structure of the fluoride lon-induced tnmenzation product of perfluorocyclobutene [74] and the products of the sodium borohydnde reduction of perfluoromdene [75] ESCA is also used to analyze and optimize gas-phase reactions, such as the bromination of trifluoro-methane to produce bromotrifluoromethane, a valuable fire suppression agent [76] The ionization energies for several hundred fluorme-containing compounds are summarized in a recent review [77]... 

Between sodium and chlorine, there is a slow rise in ionization energy. For magnesium and aluminum the ionization energy is still rather low. Hence electrons are readily lost and positive ions can be expected to be important in the... 

Consider the three elements, sodium, magnesium, and aluminum. For each of these elements we know several ionization energies, corresponding to processes such as the following ... 

The experimental values of these energies are shown in Table 15-1V. Let us begin by comparing sodium and magnesium. For each, the first ionization process removes a 35 electron, the most weakly bound. Nevertheless, the ionization energies are somewhat different ... 

What trend is observed in the first ionization energy as you move from lithium down the column I metals On this basis, can you suggest a reason why potassium or cesium might be used in preference to sodium or lithium in photoelectric cells ... 

Experimentally we discover that AZ/(Nad) is much larger, 98.0 kcal—a discrepancy of 98 — 37 = 61 kcal. This discrepancy is explained in terms of the large difference in ionization energy of sodium and chlorine atoms ... 

Write out the electron configuration of sodium, magnesium, and aluminum and find the ionization energies for all their valence electrons (Table 20-IV, p. 374). Account for the trend in the heats of vaporization and boiling points (Table 20-1) of these elements. Compare your discussion with that given in Section 17-1.3. 

We have already mentioned that the stability of the metallic crystal and the ionization energies of the atom tend to increase in the series sodium, magnesium, and aluminum. In spite of this, aluminum is still an excellent reducing agent because the hydration energy of the Al+1 ion is very large (Table 20-III). 

Let us apply these ideas to the third-row elements. On the left side of the table we have the metallic reducing agents sodium and magnesium, which we already know have small affinity for electrons, since they have low ionization energies and are readily oxidized. It is not surprising, then, that the hydroxides of these elements, NaOH and Mg(OH)z, are solid ionic compounds made up of hydroxide ions and metal ions. Sodium hydroxide is very soluble in water and its solutions are alkaline due to the presence of the OH- ion. Sodium hydroxide is a strong base. Magnesium hydroxide, Mg(OH)2, is not very soluble in water, but it does dissolve in acid solutions because of the reaction... 

Ionization lithium, 267 magnesium, 270 sodium, 270 Ionization energy, 267 alkaline earths, 379 and atomic number, 268 and ihe periodic table, 267 and valence electrons, 269 halogens, 353 measurement of, 268 successive, 269 table of, 268 trends, 268... 

Account for the fact that the ionization energy of potassium is less than that of sodium despite the latter having the smaller effective nuclear charge. 

Ionizing sodium atoms requires that energy be supplied, the amount being the first ionization energy for sodium Na(g) Na (g) +e AE = E — 495.5 kJ/mol... 

The second ionization energy of sodium is much larger than its first ionization energy because a core 2 p electron must be removed to create Na from Na. Removal of a core electron always requires a great deal of energy, so it is a general feature of ionic systems that ions formed by removing core electrons are not found in stable ionic compounds. 

Let s consider the bond formation between sodium and chlorine, a metal and a nonmetal. The electronegativity values of sodium and chlorine are 0.9 and 3.0 respectively. This tells us that sodium has a low ionization energy and a tendency to give electrons while chlorine has a tendency to take electrons. 

Fig. 2.12 Relative orbital energies of the elements hydrogen to sodium. Solid lines indicate one-electron orbital energies. Dashed lines represent experimental ionization energies, which differ as a result of electron-electron interactions.

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