Chlorine (Cl) – Periodic Table [Element Information & More]

chlorine element periodic table

Chlorine element (Cl) is in group 17 and period 3 of a periodic table. Chlorine is in the p-block and it is classified as a halogen group element on the periodic table.

There is a lot more information related to chlorine which is mentioned in the Information Table given below.

So let’s dive right into it!

Table of contents

Chlorine Element (Information Table)

The important data related to chlorine element is given in the table below.

Appearance of chlorinePale yellow-green gas
Atomic number of chlorine17
Symbol of chlorineCl
Atomic mass of chlorine35.45 u
Protons, Neutrons & Electrons in chlorineProtons: 17, Neutrons: 18, Electrons: 17
State of chlorine (at STP)Gas
Group number of chlorine in periodic table17
Period number of chlorine in periodic table3
Block of chlorine in periodic tablep-block
Category of chlorineNonmetals (halogens)
Bohr model or Electrons per shell or Electrons arrangement in chlorine2, 8, 7
Electron configuration of chlorine[Ne] 3s2 3p5
Orbital diagram of chlorineorbital diagram of chlorine
Valence electrons in chlorine7
Electronegativity of chlorine (on pauling scale)3.16
Atomic radius of chlorine (van der Waals radius)175 picometers
Density of chlorine3.214 g/L
1st ionization energy of chlorine12.968 eV
Main isotope of chlorine35Cl and 37Cl
Melting point of chlorine (Cl2)171.6 K or -101.5 °C or -105.7 °F
Boiling point of chlorine (Cl2)239.11 K or -34.04 °C or -29.27 °F
Crystal structure of chlorineOrthorhombic
Discovery of chlorineBy Carl Wilhelm Scheele in 1774

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).

Chlorine element in Periodic table

The Chlorine element (Cl) has the atomic number 17 and is located in group 17 and period 3. Chlorine is a nonmetal and it is classified as a halogen element.

Click on above elements in the periodic table to see their information.

Facts about chlorine

Here are a few interesting facts about chlorine element.

  1. The chlorine element is given its name from the Greek word “khloros” which means “greenish-yellow” (which is the appearance of the chlorine gas).
  2. Chlorine is the 3rd most abundant element present in the ocean.
  3. Chlorine is the 21st most abundant element present in the earth’s crust.
  4. Sea water has a very large amount of chlorine (present in NaCl in seawater).
  5. Chlorine is also present in the human body.
  6. The chlorine always exists as a diatomic molecule (i.e Cl2).
  7. We intake chlorine from food (i.e table salt (NaCl)). Inhaling a pure chlorine gas is toxic for the human body.

Properties of chlorine

Here is a list of some physical properties and chemical properties of chlorine.

Physical properties of chlorine

  • Chlorine gas has a pale yellow-green color appearance.
  • Chlorine gas has a strong smell.
  • The atomic mass of chlorine is 35.45 u and its density is 3.214 g/L.
  • The melting point and boiling point of chlorine (Cl2) is 171.6 K and 239.11 K respectively.

Chemical properties of chlorine

  • Chlorine shows chemical reaction with many elements because it has higher electronegativity and high electron affinity.
  • Chlorine is a reactive nonmetal and hence it is always found with other compounds.
  • Chlorine does not show any reaction with lighter noble gases, because the noble gases are chemically inert.
  • Chlorine forms a white mist when it reacts with ammonia (NH3).
  • Chlorine gas is liberated on electrolysis of salt water.
  • Chlorine is a nonflammable gas and it is non explosive in nature.
  • Chlorine is also added to drinking water to kill bacteria and microorganisms.

Uses of chlorine

Here are some uses of the chlorine element.

  • Chlorine was once used as a chemical weapon which can burn the skin.
  • Chlorine is also used in manufacturing of medicines, disinfectants as well as insecticides.
  • The paper industries, plastic industries as well as dyes industries also used chlorine.
  • Polyvinyl Chloride (PVC) is a polymer that has chlorine in it.

External resources:

  1. Chlorine. (2022, April 5). American Chemistry Council.
  2. The Facts About Chlorine. (2005, May 1). The Facts About Chlorine.
  3. Chlorine – Wikipedia. (2008, July 10). Chlorine – Wikipedia.
  4. Chlorine | Cl | ChemSpider. (n.d.). Chlorine | Cl | ChemSpider.
  5. Atomic Data for Chlorine (Cl). (n.d.). Atomic Data for Chlorine (Cl).
  6. Periodic Table of Elements: Los Alamos National Laboratory. (n.d.). Periodic Table of Elements: Los Alamos National Laboratory.
  7. Haynes, W. M. (Ed.). (2014, June 4). CRC Handbook of Chemistry and Physics.
  8. James A. M. & Lord M. P. (1992). Macmillan’s chemical and physical data. Macmillan.
  9. Holden, et al. (2018, December 1). IUPAC Periodic Table of the Elements and Isotopes (IPTEI) for the Education Community (IUPAC Technical Report). Pure and Applied Chemistry, 90(12), 1833–2092.
  10. Allred, A. (1961, June). Electronegativity values from thermochemical data. Journal of Inorganic and Nuclear Chemistry, 17(3–4), 215–221.
  11. Kaye, G W.C., & Laby, T H. Tables of physical and chemical constants. 15th Edition. United States.
  12. Emsley, J. (2011). Nature’s Building Blocks: An A-Z Guide to the Elements. United Kingdom: OUP Oxford.
  13. Sansonetti, J. E., & Martin, W. C. (2005, December). Handbook of Basic Atomic Spectroscopic Data. Journal of Physical and Chemical Reference Data, 34(4), 1559–2259.
  14. Bondi, A. (1964, March). van der Waals Volumes and Radii. The Journal of Physical Chemistry, 68(3), 441–451.
  15. Zhang, Y., Evans, J. R. G., & Yang, S. (2011, January 11). Corrected Values for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks. Journal of Chemical & Engineering Data, 56(2), 328–337.
  16. Possolo, A., van der Veen, A. M. H., Meija, J., & Hibbert, D. B. (2018, January 4). Interpreting and propagating the uncertainty of the standard atomic weights (IUPAC Technical Report). Pure and Applied Chemistry, 90(2), 395–424.

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