Introduction

This unit turns to two of the most reactive families in the periodic table: the alkali metals (Group 1) and the alkaline earth metals (Group 2), together called the s-block elements because their outermost (differentiating) electron always occupies an s orbital.

What this unit sets out to do. By the end of it you should be able to:

• explain the general properties of alkali metals and alkaline earth metals, and why both families are so reactive;
• recognise the anomalous properties of the first member of each family -- lithium (Li) and beryllium (Be) -- compared with the rest of their group;
• list the practical uses of alkali and alkaline earth metals and their compounds;
• describe the general characteristics of the important compounds these two families form;
• appreciate the biological importance of sodium, potassium, magnesium and calcium in living systems;
• explain the preparation, properties and uses of four everyday calcium compounds: calcium oxide (quicklime), calcium hydroxide (slaked lime), gypsum and plaster of Paris.