Mercury ionization energy

Table 18.2 Occupation probability of the valence orbital of a few alkali and halide ions adsorbed on mercury ( = 4.5 eV). For alkali atoms eo denotes the ionization energy for halide atoms, the electron affinity.

The mercury atom is smaller than expected from the zinc-cadmium trend and is more difficult to ionize than the lighter atoms. In consequence the metal-metal bonding in mercury is relatively poor, resulting in the element being a liquid in its standard state. This almost Group 18 behaviour of mercury may be compared to that of a real Group 18 element, xenon, which has first and second ionization energies of 1170 and 2050 kJ mol. ... 

The increased ionization energies of the heavier transition metals should not be unexpected by anyone who has had a modicum of laboratory experience with any of these elements. Although none of the coinage metals is very reactive, gold has a well-deserved reputation for being less reactive than copper or silver iron, cobalt, and nickel rust and corrode, but osmium, indium, and platinum are noble and unreaclive and therefore are used in jewelry platinum wires are the material of choice fior flame tests without contamination and one generates hydrogen with zinc and simple adds, not with mercury. 

Photoelectron spectra of mercury (Hg) atoms acquired with radiation from a helium lamp at 584.4 A show a peak in which the photoelectrons have kinetic energy of 11.7 eV. Calculate the ionization energy of electrons in that level. 

Table 3. Vertical ionization energies / (in eV) of gaseous zinc(II), cadmium(II) and mercury (II) compounds. The lowest / corresponds to a M.O. with symmetry type (and oj = 3/2 in spin-orbit coupling) mainly consisting of halide n pn orbitals (carbon a in the case of dimethylmercury). Further on, the d-like components at high / are given in two groups (separated by a semi-colon) with 2Ds/2 at lower and 2D3/2 at higher /.

Zinc and cadmium dissolve in dilute acid to give their -I- 2 ions, but mercury does not dissolve, as indicated by the two positive reduction potentials. Mercury forms the diatomic Hg2 ion, in which the Hg-Hg bond length is 251 pm, consistent with it being a single ct bond formed from the overlap of the two 6s atomic orbitals. The reason for the relatively greater stability of the 6s electrons of Hg is relativistic stabilization which causes the first two ionization energies (1010 and 1810 kJ mol ) to be considerably greater than those of Zn (908 and 1730 kJ mol ) and Cd (866 and 1630 kJ mol ). 

---