Atomic Number 4

What Element is Atomic Number 4?

Element atomic number 4 or beryllium was used to make the lenses of these 18th century Chinese glasses.
Element atomic number 4 or beryllium was used to make the lenses of these 18th century Chinese glasses. De Agostini / A. Dagli Orti, Getty Images

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.

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.
  • 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 f beryllium copper. This is copper with the addition of a small amount of beryllium, which makes the metal six times stronger than it would be in pure form.
  • 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, camera, analytical lab equipment, and in the fine-tuning knobs of radios, radar equipment, thermostats, and lasers.
  • Element number 4 is produced by three countries at present -- the United States, China, and Kazakhstan.
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Your Citation
Helmenstine, Anne Marie, Ph.D. "Atomic Number 4." ThoughtCo, Sep. 2, 2015, Helmenstine, Anne Marie, Ph.D. (2015, September 2). Atomic Number 4. Retrieved from Helmenstine, Anne Marie, Ph.D. "Atomic Number 4." ThoughtCo. (accessed March 20, 2018).