Group 2 The Alkaline Earth Metals

The elements in group 2, the alkaline earth metals, show an oxidation number of +2 in all compounds. 

The s-block includes group 1 (the alkali metals) and group 2 (the alkaline earth metals) plus hydrogen and helium. The element hydrogen is placed in group 1 for convenience (International Union of Pure and Applied Chemistry [lUPAC] 2011) due to its electron configuration (ns ) but it is not an alkali metal. 

Because it is in Group 1 (the alkali metals), this element is likely to be more reactive than the element described in (a), which is in Group 2 (the alkaline-earth metals). 

The Group 2 or alkaline earth metals exemplify and continue the trends in properties noted for the alkali metals. No new principles are involved, but the ideas developed in the preceding chapter gain empha.sis and clarity by their further application and extension. Indeed, there is an impressively close parallelism between the two groups as will become increasingly clear throughout the chapter. 

E9.2 The group is the alkaline earth metals or Group 2 elements. Consult Sections 12.8 and 12.9 for detailed reactions. 

Group lA (or 1) elements are also known as the alkali metals Group IIA (or 2), the alkaline earth metals Group VIIA (or 17), the halogens and Group VIIIA (or 18), the noble gases. 

Family Portrait of Group 2A(2) The Alkaline Earth Metals... 

To round off the discussion, we now move simultaneously east into Group 2 and west into Group 16. The alkaline-earth-metal atoms can surrender two electrons, and the oxygenlike atoms can each accept two. So once again we have the pattern of compounds in which for each atom of Group 2 there will be one atom of Group 16. This pattern matches exactly what is observed, and accounts for the composition of compounds like lime (calcium oxide, one calcium ion to one oxide ion). 

Solution (a) and F are isoelectronic anions, both containing 10 electrons. Because has only seven protons and F has nine, the weaker attraction exerted by the nucleus of makes it the larger ion. (b) Both Mg and Ca belong to Group 2A (the alkaline earth metals). Thus, Ca ion is larger than Mg " because the outer electrons in are in a larger shell (n = 3) than are the outer electrons in Mg (n = 2). 

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