Lithium is in the "alkali metals" group in the periodic table of the elements. Elements in the alkali metals group, also known as Group 1A, each have one electron in its outer shell and other distinct, shared properties.
Other alkali metals include lithium, sodium, potassium and francium. These metals are shiny and soft enough to be cut through with a knife, and they oxidize rapidly when exposed to any source of oxygen. The single, outer electron is easily excited and causes a distinctive flame color in each element, such as crimson for lithium or blue-violet for rubidium. The alkali metals are the most homogenous of any elemental family.