Atomic Number 4 Element Facts

What Element is Atomic Number 4?

Beryllium atom

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Beryllium is the element that is atomic number 4 on the periodic table. It is the first alkaline earth metal, located at the top of the second column or group of the periodic table. Beryllium is a relatively rare element in the universe and not a metal most people have seen in pure form. It is a brittle, steel-gray solid at room temperature.

Fast Facts: Atomic Number 4

  • Element Name: Beryllium
  • Element Symbol: Be
  • Atomic Number: 4
  • Atomic Weight: 9.012
  • Classification: Alkaline Earth Metal
  • Phase: Solid Metal
  • Appearance: White-Gray Metallic
  • Discovered By: Louis Nicolas Vauquelin (1798)

Element Facts for Atomic Number 4

  • The element with atomic number 4 is beryllium, which means each atom of beryllium has 4 protons. A stable atom would have 4 neutrons and 4 electrons. Varying the number of neutrons changes the isotope of beryllium, while varying the number of electrons can make beryllium ions.
  • The symbol for atomic number 4 is Be.
  • Element atomic number 4 was discovered by Louis Nicolas Vauquelin, who also discovered the element chromium. Vauquelin recognized the element in emeralds in 1797.
  • Beryllium is an element found in beryl gemstones, which include emerald, aquamarine, and morganite. The element name comes from the gemstone, as Vauquelin used beryl as the source material when purifying the element.
  • At one time the element was called glucine and had the element symbol Gl, to reflect the sweet taste of the element's salts. Although the element tastes sweet, it is toxic, so you shouldn't eat it! Inhalation beryllium can cause lung cancer. There is no cure for beryllium disease. Interestingly, not everyone who is exposed to beryllium has a reaction to it. There is a genetic risk factor that causes susceptible individuals to have an allergic inflammatory response to beryllium ions.
  • Beryllium is a lead-gray metal. It is stiff, hard, and nonmagnetic. Its modulus of elasticity is about a third higher than that of steel.
  • Element atomic number 4 is one of the lightest metals. It has the one of the highest melting points of the light metals. It has exceptional thermal conductivity. Beryllium resists oxidation in air and also resists concentrated nitric acid.
  • Beryllium is not found in pure form in nature, but in combination with other elements. It is relatively rare in the Earth's crust, found at an abundance of 2 to 6 parts per million. Trace amounts of beryllium are found in seawater and air, with slightly higher levels in freshwater streams.
  • One use of element atomic number 4 is in the production of beryllium copper. This is copper with the addition of a small amount of beryllium, which makes the alloy six times stronger than it would be as a pure element.
  • Beryllium is used in x-ray tubes because its low atomic weight means it has a low absorption of x-rays.
  • The element is the main ingredient used to make the mirror for NASA's James Webb Space Telescope. Beryllium is an element of military interest, since beryllium foil may be used in the production of nuclear weapons.
  • Beryllium is used in cell phones, cameras, analytical lab equipment, and in the fine-tuning knobs of radios, radar equipment, thermostats, and lasers. It is a p-type dopant in semiconductors, which makes the element critically important for electronics. Beryllium oxide is an excellent thermal conductor and electrical insulator. The element's rigidity and low weight make it ideal for speaker drivers. However, expense and toxicity limits its use to high-end speaker systems.
  • Element number 4 is produced by three countries at present: the United States, China, and Kazakhstan. Russia is returning to beryllium production after a 20-year break. Extracting the element from its ore is difficult because of how readily it reacts with oxygen. Usually, beryllium is obtained from beryl. Beryl is sintered by heating it with sodium fluorosilicate and soda. The sodium fluoroberyllate from sintering is reacted with sodium hydroxide to form beryllium hydroxide Beryllium hydroxide is converted to beryllium fluoride or beryllium chloride, from which beryllium metal is obtained by electrolysis. In addition to the sintering method, a melt method may be used to produce beryllium hydroxide.


  • Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 14.48. 
  • Meija, J.; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91.
  • Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110.
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Helmenstine, Anne Marie, Ph.D. "Atomic Number 4 Element Facts." ThoughtCo, Sep. 7, 2021, Helmenstine, Anne Marie, Ph.D. (2021, September 7). Atomic Number 4 Element Facts. Retrieved from Helmenstine, Anne Marie, Ph.D. "Atomic Number 4 Element Facts." ThoughtCo. (accessed June 1, 2023).