Astatine ionization energy

Aromatic compounds, 344 Arrhenius, Svante, 198 Arsenic, ionization energy, 410 Asbestos, 310 Aspirin, 346 Astatine... 

It was noted above that discussion of astatine together with the other halogens is inconvenient. Although it is, as expected, the most metallic of the halogens, there arc few values or experimental data to cite in support of this. (Note for example that such fundamental quantities as experimental ionization energies are unavailable.) Various isotopes ok astatine arc produced only in trace amounts, with half-lives of a few hours or less, and therefore the chemistry of astatine is essentially the descriptive chemistry obtained by tracer methods macroscopic amounts arc not available. The best known oxidation state of astatine is — I. Astatine may be readily reduced to as ta tide ... 

Can you use data in Tabie 7.7 to provide estimates for the atomic radius and first ionization energy of an astatine atom ... 

Figure 7.10 First ionization energies for the representative elements in the first six periods. The ionization energy generally increases from left to right and decreases from top to bottom. The ionization energy of astatine has not been determined. 

From Figure 8.18, predict the first ionization energy of astatine (Z = 85). 

The melting points show a pattern, or trend, down the group. It is therefore possible to predict that the melting point of astatine is approximately 380 °C. The same can be done with other physical properties, such as the melting points, and atomic properties, such as first ionization energy. 

Use graphs to plot the melting points, eiectron affinity vaiues and first ionization energies for the haiogens fiuorine, chiorine, bromine and iodine (group 17 eiements). Extrapoiate the smooth curves to estimate the vaiues for astatine. Compare your vaiues with the vaiues on the pages 7 and 8 of the IB Chemistry data booklet... 

The following properties of astatine have been measured or estimated (a) covalent radius (b) ionic radius (At ) (c) first ionization energy (d) electron affinity (c) electronegativity (f) standard reduction potential. Based on periodic relationships and data in Table 22.4, what values would you expect for these properties ... 

Chang, Z., Li., J., Dong, C. Ionization potentials, electron affinities, resonance excitation energies, oscillator strengths, and ionic radii of element Uus (Z = 117) and astatine. J. Phys. Chem. A 114, 13388-13394 (2010)... 

---