Exercise 21 Solution
Using an internet search, it was determined that all the alkali metals have one electron in their outermost shell and all the alkaline earth metals have two outer electrons. Alkali metals tend to form singly charged positive ions while alkaline earth metals tend to form cations with a +2 charge. To achieve the inert noble gas configuration, alkali metals need to lose one electron (valence is “one”), whereas alkaline earth metals need to lose two electrons (valence is “two”). Thus, alkali metals tend to form singly charged positive ions while alkaline earth metals tend to form cations with a +2 charge. If this is confusing, it will be useful to review an inorganic chemistry textbook (or other source of basic inorganic chemistry information) and to learn how the periodic table of elements is organized.