Groups :

 Alkali Metals

Tool: Interactive Periodic Table

About the Group
The first column of the periodic table is the group of elements known as the Group 1 or alkali metals. This group includes lithium, sodium, potassium, rubidium, cesium, and francium. By definition, a metal is an element that loses one or more electrons to create a positively charged ion known as a cation (pronounced "cat"- "ion"). The alkali metals have only one electron in their outermost energy level. All elements would like to have complete s and p orbitals in their outermost energy levels, an arrangement of eight electrons called an octet. The rule of thumb for creating any type of ion is called the Octet Rule. The Octet Rule says that elements lose, gain, or share electrons to form the required octet in their highest remaining energy level.

Chemical Properties
The alkali metals are the most reactive of all of the metals. Adding them to water causes the hydrogen in the water to be released as a gas, and the formation of very strong bases known as hydroxides. The release of hydrogen is also accompanied by a release of energy during the reaction. For example, adding metallic lithium to water will cause strong fizzing and bubbling with a slight increase of heat. Adding metallic sodium to water will cause more rapid production of hydrogen gas. But adding even a small amount of potassium to water will release a large enough amount of energy to cause an explosion and fire as the hydrogen gas is released and ignited.

In the "Real" World
When metals combine with nonmetals they form a class of chemicals known as salts. The common table salt you use every day is a compound of sodium, an alkali metal, and chlorine, a very reactive nonmetal. Other salts are formed when a different metal or nonmetal is used. Salt substitutes are often potassium chloride compounds. The potassium is used instead of sodium to create the compound. This allows people to control the sodium intake in their daily meals.

Illustration highlighting the alkali metals on the periodic table