What is the alkali metal triad?

The alkali metal triad refers to the grouping of three alkali metals: lithium (Li), sodium (Na), and potassium (K). These metals are found in Group 1 of the Periodic Table and share similar chemical properties, such as their high reactivity with water and tendency to form positive ions. The triad illustrates the trend of increasing reactivity and decreasing ionization energy as you move down the group from lithium to potassium. This trend is attributed to the increasing atomic size and decreasing effective nuclear charge experienced by the outermost electron.