Atomic Number 3 Element Facts

What Element is Atomic Number 3?

Each atom of atomic number 3 has three protons. Lithium may have a different number of neutrons and electrons, depending on the isotope or ion.
Each atom of atomic number 3 has three protons. Lithium may have a different number of neutrons and electrons, depending on the isotope or ion. ROGER HARRIS/SCIENCE PHOTO LIBRARY / Getty Images

Lithium is the element that is atomic number 3 on the periodic table. These means each atom contains 3 protons. Lithium is a soft, silvery, light alkali metal denoted with the symbol Li. Here are interesting facts about atomic number 3:

  • Lithium is the lightest metal and the lightest solid element at ordinary temperature and pressure. It also has the highest specific heat capacity of a solid element.
  • Element number 3 is soft enough to cut with shears and light enough to float on water.
  • Among its uses, lithium is used in medications for bipolar disorder, to make lithium ion batteries, and to add a red color to fireworks. It's also used in glass and ceramics and to make high temperature lubricant grease. It is a coolant in breeder reactors and a source of tritium when atomic number 3 is bombarded with neutrons.
  • Lithium is the only alkali metal that reacts with nitrogen. Yet, it is the least reactive metal in its element group. While it burns in water, it does not do so as vigorously as sodium or potassium. Lithium metal will burn in air and should be stored under kerosene or in an inert atmosphere, like argon. Don't try to extinguish a lithium fire with water -- it will only make it worse!
  • Because the human body contains a lot of water, lithium will also burn skin. It is corrosive and should not be handled without protective gear.
  • The name for the element comes from the Greek word "lithos", which means "stone". Lithium was discovered in the mineral petalite (LiAISi4O10). Brazilian naturalist and statesman, Jozé Bonifácio de Andralda e Silva found the stone on the Swedish isle Utö. Although the mineral looked like an ordinary gray rock, it flared red when thrown into a fire. Swedish chemist Johan August Arfvedson determined the mineral contained a previously unknown element. He couldn't isolate a pure specimen, but did produce a lithium salt from petalite in 1817.
  • The atomic mass of lithium is 6.941. It's density is 0.52 grams per cubic centimeter, which means it not only floats on water, but is just over half as dense!
  • Lithium is believed to be one of only three chemical elements produced in the Big Bang that formed the universe. The other two elements are hydrogen and helium.
  • Several isotopes of lithium are known, but the natural element is a mix of two stable isotopes. Li-7 (92.41 percent natural abundance) and Li-6 (7.59 percent natural abundance).
  • Lithium readily loses its outer electron to form the Li+ ion. This leaves the atom with a stable inner shell of two electrons. The lithium ion readily conducts electricity.
  • Because of its high reactivity, lithium is not found in nature as a pure element, but the ion is abundant in sea water. Lithium compounds are found in clay.
  • Mankind's first fusion reaction involved atomic number 3, in which lithium was used to make hydrogen isotopes for fusion by Mark Oliphant in 1932.
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Helmenstine, Anne Marie, Ph.D. "Atomic Number 3 Element Facts." ThoughtCo, Apr. 10, 2016, Helmenstine, Anne Marie, Ph.D. (2016, April 10). Atomic Number 3 Element Facts. Retrieved from Helmenstine, Anne Marie, Ph.D. "Atomic Number 3 Element Facts." ThoughtCo. (accessed January 19, 2018).