March 26, 2025

HELIUM

All About Chemistry07 mins
HELIUM

Helium: The Lightest Noble Gas

Introduction

Helium is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Helium is the second-lightest element and the second-most abundant element in the universe, after hydrogen.

Physical Properties

  • Atomic Number: 2
  • Atomic Mass: 4.002602 u (unified atomic mass units)
  • Boiling Point: -268.93 °C (-452.07 °F)
  • Melting Point: -272.2 °C (-458 °F)
  • Density: 0.1786 g/l (at standard temperature and pressure)
  • Solubility: Insoluble in water

Occurrence

Helium is the second-most abundant element in the universe, making up about 23% of its elemental mass. On Earth, helium is relatively rare, making up only about 0.0005 ppm (parts per million) of the atmosphere. It is primarily found in natural gas deposits, particularly in the United States, Algeria, Russia, and Qatar.

Production

Helium is extracted from natural gas through a process known as fractional distillation. The extracted helium is then purified and liquefied for use in various applications.

Uses

  • Balloons and Airships: Helium is lighter than air, making it an ideal lifting gas for balloons and airships.
  • Cryogenics: Liquid helium is used as a cryogenic fluid to cool superconducting materials, such as those used in magnetic resonance imaging (MRI) machines.
  • Welding: Helium is used as a shielding gas in welding processes, such as TIG (tungsten inert gas) and MIG (metal inert gas) welding.
  • Medical Applications: Helium is used as a cooling medium for superconducting magnets in MRI machines and as a gas for respiratory therapy.
  • Space Exploration: Liquid helium is used as a fuel component in some rocket engines.
Helium

Fundamental Properties:

  • Atomic Structure:
    • Helium’s atomic structure consists of a nucleus with two protons and, in the most common isotope (helium-4), two neutrons.
    • It has two electrons in its outermost shell, making it a noble gas.
  • Physical Properties:
    • Helium is a colorless, odorless, tasteless, and non-toxic gas.
    • It has the lowest boiling point of any element (-268.93 °C).
    • It remains a gas down to extremely low temperatures at normal pressures.
    • It is the second lightest element, after hydrogen.
    • It is exceptionally inert, meaning it rarely reacts with other elements.
  • Chemical Properties:
    • Helium is a noble gas, which means it is chemically unreactive under normal conditions.
    • It does not readily form chemical compounds.

Occurrence:

  • In the Universe:
    • Helium is the second most abundant element in the universe, after hydrogen.
    • It is primarily formed through nuclear fusion in stars.
  • On Earth:
    • Helium is relatively rare in Earth’s atmosphere, making up only a tiny fraction of its composition.
    • It is primarily obtained from natural gas deposits, where it accumulates due to the radioactive decay of uranium and thorium in the Earth’s crust.

Applications:

  • Cryogenics:
    • Liquid helium is crucial for achieving extremely low temperatures, essential for superconducting magnets in MRI machines and scientific research.
  • Lifting Gas:
    • Helium’s low density makes it ideal for filling balloons and airships.
  • Welding:
    • Helium is used as a shielding gas in welding to prevent unwanted reactions with atmospheric gases.
  • Diving:
    • Helium is mixed with oxygen to create breathing gases for deep-sea diving, preventing nitrogen narcosis.
  • Leak Detection:
    • Helium’s small atomic size allows it to penetrate tiny leaks, making it useful for detecting leaks in pipelines and equipment.
  • Scientific Research:
    • Helium is used in many scientific applications, including in particle accelerators.

Key Points:

  • Helium’s inertness and extremely low boiling point make it invaluable in various scientific and industrial applications.
  • The earths supply of helium is a non renewable resource.

Interesting Facts

  • Helium is the only element that cannot be solidified at normal pressure.
  • The voice of a person who inhales helium becomes high-pitched and squeaky due to the lower density of helium compared to air.
  • The first helium-filled balloon was flown by French inventor Henri Giffard in 1852.

Bibliography:


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