Barium ionization energy

On the basis of your knowledge of periodicity, place each of the following sets of elements in order of decreasing ionization energy. Explain your choices, (a) Selenium, oxygen, tellurium (b) gold, tantalum, osmium (c) lead, barium, cesium. 

Barium is almost as powerful a reducing agent as is Cs. but La is somewhat less so. The appropriate sums of the ionization energies and the enthalpies of atomization compete well with the enthalpies of hydration for Cs and Ba, but the enthalpy of hydration of the La 1"1" ion is not sufficiently negative to outweigh the large third ionization energy. 

An s-block element has a low ionization energy, which means its outermost electrons can be lost easily. A Group 1 element is likely to form +1 ions, such as Li+, Na+, and K+. Group 2 elements similarly form +2 ions, such as Mg2+, Ca2+, and Ba2+. An s-block element is likely to be a reactive metal with all the features that the name metal implies (Fig. 1.48, Table 1.4). Because ionization energies are lowest at the bottom of each group, and the elements there lose their valence electrons most easily, the heavy elements cesium and barium react most vigorously of all s-block elements. They have to be kept stored out of contact with air and water. The alkali metals have few direct uses as materials but are enormously important as compounds. 

Place the following in order of increasing first ionization energy magnesium, calcium, barium. 

Q20 Barium, with an atomic number of 56, is an element in group 2 of the periodic table (below strontium with atomic number 56). Which of the following statements about barium is not correct A Its first ionization energy is lower than that of strontium,... 

Figure 7.15 shows samples of the Group 2 A elements. As a group, the alkaline earth metals are somewhat less reactive than the alkali metals. Both the first and the second ionization energies decrease (and metalilc character increases) from beryllium to barium. Group 2A elements tend to form ions, where M denotes an alkaline earth metal atom. 

Dithiocarbamates have been prepared from a wide range of amino acids (Fig. 20) (119-123). They are usually generated as the barium salts upon addition of barium hydroxide to the amino acid in the presence of carbon disulfide. Macias et al. (124) measured the ionization energies of various a-amino acid dithiocarbamates by X-ray photoelectron spectroscopy (XPS) and find that they increase as the side chain becomes longer probably being related to the change in donor ability. They react with transition metal salts to afford complexes in much the same way as simple dithiocarbamates (122, 125-138), although in some instances metal coordination of the carboxylate moiety is also proposed (119). 

The first ionization energies of the Group II and Group III elements. There is a marked decrease between magnesium and barium, which is not matched by that between aluminium and thallium. 

It is perhaps significant that distinct 4 p 1j2 and 4 p3/2 energies are found (139) in X-ray spectra of silver (/ = 55.9 and 62.6 eV), caesium (161.6 and 172.3 eV) and barium, but not in the interval (Z between 48 and 54) where the value given seems to refer to 4 p3 2. This situation suggests that the lack of definition of a sharp energy of the ionized system lacking a 4p 1j2 electron also occurs in the final states of X-ray emission where, for instance, a 4p electron jumps down in a vacant 1 s or 3 d position. 

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