
Selenium element (Se) is in group 16 and period 4 of a periodic table. Selenium is in the p-block and it is classified as a carbon group element (chalcogens) on the periodic table.
There is a lot more information related to selenium which is mentioned in the Information Table given below.
So let’s dive right into it!
Table of contents
- Selenium element (Information Table)
- Selenium element in Periodic table
- Facts about Selenium
- Properties of Selenium
- Uses of Selenium
Selenium Element (Information Table)
The important data related to selenium element is given in the table below.
Appearance of selenium | Hexagonal selenium has Metallic gray color Monoclinic selenium has Deep red color |
Atomic number of selenium | 34 |
Symbol of selenium | Se |
Atomic mass of selenium | 78.971 u |
Protons, Neutrons & Electrons in selenium | Protons: 34, Neutrons: 45, Electrons: 34 |
State of selenium (at STP) | Solid |
Group number of selenium in periodic table | 16 |
Period number of selenium in periodic table | 4 |
Block of selenium in periodic table | p-block |
Category of selenium | Nonmetals (Chalcogens) |
Bohr model or Electrons per shell or Electrons arrangement in selenium | 2, 8, 18, 6 |
Electron configuration of selenium | [Ar] 3d10 4s2 4p4 |
Orbital diagram of selenium | ![]() |
Valence electrons in selenium | 6 |
Electronegativity of selenium (on pauling scale) | 2.55 |
Atomic radius of selenium (van der Waals radius) | 190 picometers |
Density of selenium | 4.82 g/cm3 |
1st ionization energy of selenium | 9.752 eV |
Main isotope of selenium | 80Se |
Melting point of selenium | 494 K or 221 °C or 430 °F |
Boiling point of selenium | 958 K or 685 °C or 1265 °F |
Crystal structure of selenium | Hexagonal |
Discovery of selenium | By Jöns Jakob Berzelius and Johann Gottlieb Gahn (in 1817) |
Also see: Interactive Periodic Table (It has rotating bohr models as well as many other details of all the 118 elements in a single periodic table).
Selenium element in Periodic table
The Selenium element (Se) has the atomic number 34 and is located in group 16 and period 4. Selenium is a nonmetal and it is classified as a chalcogen element.
H | He | ||||||||||||||||
Li | Be | B | C | N | O | F | Ne | ||||||||||
Na | Mg | Al | Si | P | S | Cl | Ar | ||||||||||
K | Ca | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr |
Rb | Sr | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe |
Cs | Ba | La* | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Rn |
Fr | Ra | Ac** | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og |
*Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | ||||
**Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr |
Facts about selenium
Here are a few interesting facts about selenium element.
- The name selenium came from the Greek word “Selene”, which means moon.
- Selenium was discovered by Jöns Jakob Berzelius and Johann Gottlieb Gahn in 1817.
- Selenium has different colors as well as different crystal structures.
- The monoclinic selenium has deep red color while the hexagonal selenium has metallic gray color.
- The annual production of selenium in the entire world is around 2000 tons.
- The majority of selenium (around 50% of the total production) is used in the manufacturing of glass.
Properties of selenium
Here is a list of some physical properties and chemical properties of selenium.
Physical properties of selenium
- Selenium is a nonmetal and it has different crystal structures (depending on the temperatures). The monoclinic selenium has brick red color while the hexagonal selenium has metallic gray color.
- Selenium behaves like a semiconductor and hence it is used in photocells.
- Selenium has many isotopes, out of which 80Se is the most abundant.
Chemical properties of selenium
- Selenium reacts with oxygen to form two oxides (SeO2 and SeO3).
- Selenium reacts with halogens like fluorine, chlorine and bromine to form respective selenium halides.
- Selenium reacts with cyanides to form selenocyanates.
Uses of selenium
Here are some uses of the selenium element.
- The major use of selenium (around 50% of total production) is in manufacturing of glass.
- Selenium is also used in making pigments.
- Selenium has the properties of a semiconductor and hence it is also used in photocells.
- Selenium is also used with bismuth in making brasses.
- Selenium is used in copper alloys to improve the machinability of copper alloys.
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