Properties, Uses, & Isotopes of Fluorine + MCQs


Fluorine is the first member of the halogen group with several electrons and protons 9. The atomic weight of fluorine is 19.

Naming and History

The name fluorine (actually fluorspar) is derived from Latin “fluere” which means ‘to flow’. Basically, it was the name of mineral fluorspar, and fluorine was named accordingly.

The early chemists somehow knew about fluorine as an unidentified element and were unable to isolate it from metal fluorides. In 1812, the French physicist and mathematician Andre ampere suggested the name fluorine.

Even sir Humphry Davy was unable to isolate it and became ill in pursuing experiments for the isolation of fluorine. In 1813, he finally announced the discovery and identification of fluorine as a new element.

In 1886, French chemist, Henri Moissan was finally succeeded in isolating fluorine. He passed an electric current through hydrogen fluoride and obtained fluorine gas.

Occurrence of Fluorine

The fluorine is Earth’s 13th most abundant element and makes 0.06% of Earth’s crust. It is highly reactive so never be present in free form. It is present in minerals such as fluorspar, fluorapatite, and cryolite.

Fluorine is commercially obtained from fluorspar. China and Mexico are major suppliers of fluorspar to the world.

Properties of Fluorine

Fluorine is a highly reactive, univalent, vicious, poisonous, pale yellowish-green gas with the most electronegative element of all the elements in the periodic table. It usually forms an F- ion. It acts as a weak acid and on reacting it accepts electrons.

Fluorine is a highly reactive element; it readily forms compounds even with noble gases. It is so reactive that it can burn metals, water end glass with its bright flame. The melting point of fluorine is -219.62°C and the boiling point is -188.12°C. the density of fluorine is 0.001696 grams per cubic centimeter.

Fluorine in biological systems

Fluorine is essential for living things, animals, and plants. Fluorine is added to toothpaste and drinking water to prevent tooth decay and cavities. It is also important for strengthening bones. But the high amount and elemental fluorine are highly toxic.


Uses of Fluorine

Fluorine, fluorine salts, and their fluorides are used for welding purposes and frosting glass.

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It is of crucial importance in the nuclear energy industry.

Uranium hexafluoride is prepared from it to separate uranium isotopes.


Fluorine is used in rocket fuels, polymer, and plastic production.

Sulfur hexafluoride is a gas utilized to insulate high-power electrical power transformers.

Atomic fluorine and molecular fluorine are used for plasma etching in semiconductor manufacturing, flat panel display screen production, and MEMs fabrication.

Chlorofluorohydrocarbons are used thoroughly in air conditioners and in refrigeration systems and aerosol sprays but are now replaced as they are major destructors of the ozone layer.

Fluorochemicals, consisting of numerous high-temperature plastics such as Teflon, are also used fluorine.

Fluorine is added to city water supplies in the percentage of about one part per million to assist prevent dental caries.

Sodium fluoride (NaF), stannous(II) fluoride (SnF2), and salt monofluorophosphate (Na2PO3F) are all fluorine compounds added to tooth paste, likewise to assist avoid dental caries.


There is only one naturally occurring isotope of fluorine, fluorine-19. Only one radioactive isotope of fluorine, fluorine-18, has been prepared. Fluorine-18 is sometimes utilized for medical research studies. It is injected into the body where it takes a trip mostly to bones.

Its presence in bones can be discovered by the radiation it gives off. The radiation pattern divulges how typical bones are. Fluorine-18 is often used in a comparable way to study brain function.

MCQs with Answers: Properties, Uses, & Isotopes of Fluorine

  1. What is the atomic weight of fluorine?
    • A) 9
    • B) 19
    • C) 29
    • D) 39

    Answer: B) 19

  2. What does the name “fluorine” (fluorspar) derive from?
    • A) Latin “flux”
    • B) Latin “fluere” (‘to flow’)
    • C) Greek “fluoros” (‘yellow’)
    • D) Arabic “floura” (‘sparkle’)

    Answer: B) Latin “fluere” (‘to flow’)

  3. Who successfully isolated fluorine in 1886?
    • A) Andre Ampere
    • B) Sir Humphry Davy
    • C) Henri Moissan
    • D) Antoine Lavoisier

    Answer: C) Henri Moissan

  4. From where is fluorine commercially obtained?
    • A) Fluorapatite
    • B) Cryolite
    • C) Fluorspar
    • D) Fluoride

    Answer: C) Fluorspar

  5. What is the Earth’s rank for fluorine’s abundance in the crust?
    • A) 5th
    • B) 9th
    • C) 13th
    • D) 18th

    Answer: C) 13th

  6. Which element does fluorine usually form ions with?
    • A) F-
    • B) O2-
    • C) Cl-
    • D) Na+

    Answer: A) F-

  7. What is the melting point of fluorine?
    • A) -219.62°C
    • B) -183.12°C
    • C) 0°C
    • D) 100°C

    Answer: A) -219.62°C

  8. What is the primary use of fluorine in dental care?
    • A) Strengthening bones
    • B) Preventing tooth decay
    • C) Enhancing digestion
    • D) Improving eyesight

    Answer: B) Preventing tooth decay

  9. Which industry extensively uses chlorofluorohydrocarbons?
    • A) Agriculture
    • B) Information Technology
    • C) Air conditioning and refrigeration
    • D) Automotive

    Answer: C) Air conditioning and refrigeration

  10. What is fluorine-18 primarily used for in medical studies?
  • A) Brain function studies
  • B) Bone density analysis
  • C) Cancer treatment
  • D) Cardiovascular research
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Answer: A) Brain function studies

  1. What is the color of fluorine gas?
    • A) Colorless
    • B) Blue
    • C) Yellowish-green
    • D) Red

    Answer: C) Yellowish-green

  2. What is the density of fluorine?
    • A) 0.0001 grams per cubic centimeter
    • B) 0.001 grams per cubic centimeter
    • C) 0.01 grams per cubic centimeter
    • D) 0.1 grams per cubic centimeter

    Answer: B) 0.001 grams per cubic centimeter

  3. Which mineral is a major supplier of fluorspar to the world?
    • A) Fluorapatite
    • B) Cryolite
    • C) Fluorite
    • D) Fluoride

    Answer: C) Fluorite

  4. In what form is fluorine commercially obtained?
    • A) Gas
    • B) Liquid
    • C) Solid
    • D) Plasma

    Answer: A) Gas

  5. What is the boiling point of fluorine?
    • A) -219.62°C
    • B) -183.12°C
    • C) 0°C
    • D) 100°C

    Answer: B) -183.12°C

  6. Which gas is utilized to insulate high-power electrical power transformers?
    • A) Fluorine gas
    • B) Sulfur hexafluoride
    • C) Chlorine gas
    • D) Oxygen gas

    Answer: B) Sulfur hexafluoride

  7. What is the most electronegative element in the periodic table?
    • A) Oxygen
    • B) Fluorine
    • C) Chlorine
    • D) Nitrogen

    Answer: B) Fluorine

  8. What is the primary use of sodium fluoride (NaF)?
    • A) Rocket fuels
    • B) Toothpaste
    • C) Welding
    • D) Nuclear reactors

    Answer: B) Toothpaste

  9. What does fluorine-18 emit that helps in medical studies?
    • A) X-rays
    • B) Gamma rays
    • C) Infrared radiation
    • D) Ultraviolet rays

    Answer: B) Gamma rays

  10. How many naturally occurring isotopes does fluorine have?
    • A) One
    • B) Two
    • C) Three
    • D) Four

    Answer: A) One

Wrap up

In summary, Fluorine, the first member of the halogen group, plays a significant role in various aspects, ranging from its historical discovery to its crucial presence in biological systems. Despite being Earth’s 13th most abundant element, fluorine is highly reactive and is never found in its free form due to its reactive nature. Obtained commercially from fluorspar, China and Mexico are major contributors to the world’s fluorspar supply.

Fluorine is a highly reactive and electronegative element, existing as a pale yellowish-green gas, and is essential for living organisms. It is widely used in dentistry to prevent tooth decay, and its toxic nature requires careful handling. The uses of fluorine extend to welding, glass frosting, nuclear energy, rocket fuels, and various industrial applications, including the production of high-temperature plastics like Teflon.

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The element’s isotopes, fluorine-19 and the radioactive fluorine-18, find applications in medical studies, especially in bone and brain function research. This summary encapsulates the diverse properties, applications, and significance of fluorine across scientific, industrial, and medical domains.