Electron affinity of hydrogen

Electron Affinity of Hydrogen, Deuterium, and Tritium Atoms Obtained with 300 Explicitly Correlated Gaussian Functions ... 

The bond energy of the H-H bond is 431 kJ/mol. Electron affinity of hydrogen is low (-72 kJ/mol), where hydrogen reacts in this marmer only with the most reactive metals. The ionization potential of hydrogen is relatively high (1312 kJ/mol). Hydrogen bums with a veiy hot flame and explosion in air ... 

E. A. Hylleraas, Z. Physik 63, 771 (1930). The calculated value of the crystal energy is 219 kcal/mole, and the Born-Haber cycle value is 218 kcal/mole, using for the electron affinity of hydrogen the reliable quantum-mechanical value 16.480 kcal/mole (see Introduction to Quantum Mechanics, Sec. 29c). The calculated value for the lattice constant, 4.42 A, is less reliable than the value... 

The electron affinity E of the halogens is indeed positive, but for oxygen and sulphur energy is necessary to form a two-fold negative ion, namely about 150 and 90 kcal/gr.atom. (Actually 71 and 48 keal/gr. atom respectively, are set free in the formation of O- and S ). The electron affinity of hydrogen is weakly positive 16.5 kcal/gr.atom are set free in the formation of H. ... 

Electron affinity of Hydrogen, Deuterium and Tritium. The term AEcorr contains relativistic, relativistic recoil, Lamb shift and finite nuclear size corrections... 

In the first half of the twentieth century, positive-ion molecule reactions and the interaction of hyperthermal electrons with molecules were emphasized. Some thermal electron molecule reactions in flames and electron swarms were investigated [3]. Prior to 1950 only the electron affinities of hydrogen and the halogen atoms had been measured. A 1953 review on electron affinities noted... 

Prior to 1950 only the electron affinities of hydrogen and the halogens had been measured. The most accurate value of the electron affinity of the hydrogen atom was calculated [4]. The Ea of the halogens that agree with current values were the Bom Haber cycle values. Very few molecular electron affinities had been measured up to that point [5]. 

Kinghom, D.B. and Adamowicz, L. 1997. Electron Affinity of Hydrogen, Deuterium, and Tritium A Nonadiabatic Variational Calculation Using Explicitly Correlated Gaussian Basis Functions. Journal of Chemical Physics 106 4589-4595. 

O Malley, P.J. (1997). A density functional study of the effect of resuction on the geometry and electron affinity of hydrogen bonded 1,4-benzoquinone. Implications for quinone reduction and protonation in photosynthetic reaction centres. Chem. 

The electron affinity of hydrogen and the second ionization potential of lithium. Phys. Rev. 29 (1927) 285—291. 

Hydrogen is sometimes placed above the halogens in the periodic table because the hydrogen atom can pick up one electron to form the hydride ion, H , which has the same electron configuration as helium. The electron affinity of hydrogen (E = -73 kJ/mol), however, is not as large as tiiat of any halogen the electron affinity of fluorine is —328 kJ/mol, and tiiat of iodine is —295 kj/mol. 

The lattice energy and standard heat of formation of NaH are —782 kj/mol and — 56.3 kJ/mol, respectively. The standard heat of formation AH of H( ) is 218.0 kj/mol. Using these data and others found in Table 8.3, calculate a value for the electron affinity of hydrogen. 

Unlike the halides that occur over a wide range of the periodic table, the ionic or saline hydrides are restricted to Group lA and 2A elements. To demonstrate quantitatively why this is the case, use the values of the bond energies and the electron affinities of hydrogen and fluorine found in Table 10.3 to calculate the energy of the following process in which X = H and F ... 

In ionic compounds with certain metals, hydrogen exists as the hydride ion, H . Determine the electron affinity of hydrogen that is, for the process H(g) -I- e H (g)- To do so, use data from Section 12-7 the bond energy of H2(g) from Table 10.3 —812kJmoP for the lattice energy of NaH(s) and —57kJmoP NaH for the enthalpy of formation of NaH(s). 

Another important difference is provided by the electron affinities. The value for hydrogen is much less than that of fluorine. The small electron affinity of hydrogen becomes especially important when set alongside the much higher bond dissociation energy of the H2 molecule. 

This comparison is appropriate not just for fluorine. The electron affinity of hydrogen is much less than that of any halogen atom, and the dissociation energy of H2 is much larger than that of any of the halogen molecules. This is the main reason why ionic hydrides tend to decompose into the metal and hydrogen much more easily than do halides. 

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