This document is a chapter from a general chemistry textbook. It discusses several main-group elements and their properties. The chapter is divided into sections covering Group 1 alkali metals like lithium and sodium, Group 2 alkaline earth metals like magnesium and calcium, water hardness and softening, Group 13 metals aluminum, gallium, indium and thallium, and Group 14 metals tin and lead. For each group of elements, their discoveries, physical properties, common compounds, and industrial uses are described.