Beryllium and the Group II Elements Mg, Ca, Sr, Ba, Ra

The metal atomic radii are smaller than those of the Group I metals owing to the increased nuclear charge the number of bonding electrons in the 

Element Elec- tronic configu- ration M.p. (°Q Ionization potentials, eV A, 1st 2nd E° for M2 + (aq) + 2c = M(s) (V) Ionic radii (A)° Charge radius 

All isotopes of radium are radioactive, the longest-lived isotope being 226Ra (a 1600yr). This isotope is formed in the natural decay series of 

238U and was first isolated by Pierre and Marie Curie from pitchblende. Once widely used in radiotherapy, it is now being supplanted by radioisotopes made in nuclear reactors. 

The elements Zn, Cd, and Hg, which have two electrons outside filled penultimate d shells, are also classed in Group II. Although the difference between the calcium and zinc sub-groups is marked, Zn, and to a lesser extent Cd, show some resemblance to Be or Mg in their chemistry. We shall discuss these elements separately (Chapter 18), but it may be noted here that Zn, which has the lowest second ionization potential in the Zn, Cd, Hg group, still has a value (17.89 eV) similar to that of Be (18.21 eV), and its standard potential (—0.76 V) is considerably less negative than that of Mg. 

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Cotton FA, Wilkinson G, eds. 1980. Beryllium and the group II elements Mg, Ca, Sr, Ba, Ra. In Advanced inorganic chemistry A comprehensive text. New York, John Wiley Sons. 

The elements in Group II of the Periodic Table (alkaline earth metals) are. in alphabetical order, barium (Ba). beryllium (Be), calcium (Ca). magnesium (Mg), radium (Ra) and strontium (Sr). 

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