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Atomic Number: 34
Atomic Weight: 78.96 u
Group: 16 (oxygen group)
33 Selenium Facts for Kids
Selenium is a chemical element on the periodic table.
Selenium is a nonmetal and can vary in color from black, gray to red.
Selenium is named after Selene, the goddess of the Moon in Greek mythology.
Selenium was discovered in 1817 by Swedish chemists Jöns Jacob Berzelius and Johan Gottlieb Gahn.
The symbol for selenium is Se.
The atomic number for selenium is 34.
The standard atomic weight of selenium is 78.96 u.
Selenium is a solid at room temperature.
Selenium is in the reactive nonmental element category on the periodic table.
Selenium is a period 4 chemical element, which is the fourth row on the periodic table.
Selenium is a group 16 chemical element, which is the oxygen group.
Selenium is in the p-block on the periodic table.
The electron configuration for selenium is [Ar] 3d
10 4s 2 4p 4. The electrons per shell for selenium are 2, 8, 18, 6.
Selenium has five stable isotopes.
The five stable isotopes for selenium are
74Se, 76Se, 77Se, 78Se, and 80Se. The melting point for selenium is 430 °F (221 °C).
The boiling point for selenium is 1265 °F (685 °C).
According to the USGA, the world refined over 3 million tons of selenium in 2018.
According to the USGA, the largest refiner of selenium in 2018 was China with over 1 million tons.
According to the USGA, China refined more than 33% of the world’s supply of selenium in 2018.
Based on data from the USGA, the world’s proven reserves of selenium as of 2018 is over 109 million tons.
Based on data from the USGA, China holds over 25% of the world’s proven reserves of selenium as of 2018.
Around 50% of all selenium production goes towards glass production.
Selenium is used as an alternative to lead in several different metal alloys.
The photoconductive and photovoltaic properties of selenium make it useful for light meters, photocells and photocopying and solar cells.
Copper indium gallium selenide solar cells (CIGS cell) are made with selenium. They are a second generation solar cell that is much thinner than the first generation.
There is a lot of potential with lithium–selenium (Li–Se) batteries, it is an excellent alternative to lithium–sulfur batteries because of its high electrical conductivity.
The compound selenium dioxide (SeO
2) is used during the electrowinning of manganese to reduce the power usage needed to operate electrolysis cells. The compound zinc selenide (ZnSe) was the first compound used in LEDs for blue light, but the use of zinc selenide has faded in favor of gallium nitride.
Selenium is an essential micronutrient for animals and humans but can be toxic in big amounts.
The primary dietary source of selenium is from cereals, meats, mushrooms and nuts.
The U.S. Dietary Reference Intake (DRI) recommends a healthy adult human should intake 400 mcg of selenium a day.
Additional Resources on Selenium
Selenium (Se) – Discover more about the chemical element selenium on the Los Alamos National Laboratory website.
Selenium for Kids – Find more information about the chemical element selenium for kids on the Britannica Kids website.
Selenium and Your Health – Learn about the benefits and/or risks of selenium to your health on the National Institute of Health website.
Selenium – PubChem – Read more about selenium and the data behind it on the NIH PubChem website.