Group 1, also known as the alkali metals, consists of elements found in the first column of the periodic table. This group includes lithium, sodium, potassium, rubidium, cesium, and francium. These metals are characterized by their shiny appearance, low density, and high reactivity, especially with water. The reactivity of Group 1 elements increases as you move down the group. For example, sodium reacts vigorously with water, producing hydrogen gas and heat. Due to their high reactivity, these metals are typically stored in oil to prevent reactions with moisture and air.