Alkali Metals

The alkali metals, found in group 1 of the periodic table (formerly known as group IA), are very reactive metals that do not occur freely in nature. These metals have only one electron in their outer shell. Therefore, they are ready to lose that one electron in ionic bonding with other elements. As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals. Cesium and francium are the most reactive elements in this group. Alkali metals can explode if they are exposed to water.

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.

The Alkali Metals are:

  • Lithium (Li)
  • Sodium (Na)
  • Potassium (K)
  • Rubidium (Rb)
  • Cesium (Cs)
  • Francium (Fr)

Lithium (Li)

Name: Lithium
Symbol: Li
Atomic Number: 3
Atomic Mass: 6.941 amu
Melting Point: 180.54 °C
Boiling Point: 1347.0 °C
Number of Protons/Electrons: 3
Number of Neutrons: 4
Classification: Alkali Metals
Crystal Structure: Cubic
Density @ 293 K: 0.53 g/cm3
Color: silvery

Sodium (Na)

Name: Sodium
Symbol: Na
Atomic Number: 11
Atomic Mass: 22.98977 amu
Melting Point: 97.72 °C
Boiling Point: 883 °C
Number of Protons/Electrons: 11
Number of Neutrons: 12
Classification: Alkali Metals
Crystal Structure: Cubic
Density @ 293 K: 0.971 g/cm3
Color: silvery

Potassium

Name: Potassium
Symbol: K
Atomic Number: 19
Atomic Mass: 39.0983 amu
Melting Point: 63.65 °C
Boiling Point: 774.0 °C
Number of Protons/Electrons: 19
Number of Neutrons: 20
Classification: Alkali Metals
Crystal Structure: Cubic
Density @ 293 K: 0.862 g/cm3
Color: silvery