HELIUM GAS

 Helium with the atomic number  2 is located on the upper right side of the periodic table 

Helium (He) is a chemical element that is an inert, odorless, colorless, and tasteless gas. It belongs to the noble gases in Group 18 of the periodic table and is the second lightest element. Helium remains a liquid until cooled to −268.9 °C (−452 °F), a lower boiling and freezing point than any other known substance. It can only be solidified by applying 25 atmospheres of pressure at 1 K (−272 °C, or −458 °F).

Helium is isolated from natural gas, yielding a gas that is 98.2 percent pure. To get 99.995 percent pure helium, other gases must undergo adsorption on cooled, activated charcoal. It can also be sourced in small amounts from air liquefaction.

Helium's stable isotopes are helium-3 ((^3)He) and helium-4 ((^4)He). Superfluidity occurs in both isotopes, but at different temperatures.

Element Properties

atomic number 2

atomic weight 4.002602

melting point none

boiling point −268.9 °C (−452 °F)

density (1 atm, 0 °C) 0.1785 gram/litre

oxidation state 0

electron configuration 1s2

Helium was discovered in the gaseous atmosphere surrounding the Sun by the French astronomer Pierre Janssen, who detected a bright yellow line in the spectrum of the solar chromosphere during an eclipse in 1868; this line was initially assumed to represent the element sodium. That same year the English astronomer Joseph Norman Lockyer observed a yellow line in the solar spectrum that did not correspond to the known D1 and D2 lines of sodium, and so he named it the D3 line. Lockyer concluded that the D3 line was caused by an element in the Sun that was unknown on Earth; he and the chemist Edward Frankland used the Greek word for sun, hēlios, in naming the element. The British chemist Sir William Ramsay discovered the existence of helium on Earth in 1895

Ramsay obtained a sample of the uranium-bearing mineral cleveite, and, upon investigating the gas produced by heating the sample, he found that a unique bright yellow line in its spectrum matched that of the D3 line observed in the spectrum of the Sun; the new element of helium was thus conclusively identified. In 1903 Ramsay and Frederick Soddy further determined that helium is a product of the spontaneous disintegration of radioactive substances.

Also known as: He

 

Britannica Editors

 Dec. 4, 2025 •History

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helium (He), chemical element, inert gas of Group 18 (noble gases) of the periodic table. The second lightest element (only hydrogen is lighter), helium is a colourless, odourless, and tasteless gas that becomes liquid at −268.9 °C (−452 °F). The boiling and freezing points of helium are lower than those of any other known substance. Helium is the only element that cannot be solidified by sufficient cooling at normal atmospheric pressure; it is necessary to apply pressure of 25 atmospheres at a temperature of 1 K (−272 °C, or −458 °F) to convert it to its solid form.

Element Properties

atomic number 2

atomic weight 4.002602

melting point none

boiling point −268.9 °C (−452 °F)

density (1 atm, 0 °C) 0.1785 gram/litre

oxidation state 0

electron configuration 1s2

History

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Helium was discovered in the gaseous atmosphere surrounding the Sun by the French astronomer Pierre Janssen, who detected a bright yellow line in the spectrum of the solar chromosphere during an eclipse in 1868; this line was initially assumed to represent the element sodium. That same year the English astronomer Joseph Norman Lockyer observed a yellow line in the solar spectrum that did not correspond to the known D1 and D2 lines of sodium, and so he named it the D3 line. Lockyer concluded that the D3 line was caused by an element in the Sun that was unknown on Earth; he and the chemist Edward Frankland used the Greek word for sun, hēlios, in naming the element. The British chemist Sir William Ramsay discovered the existence of helium on Earth in 1895. Ramsay obtained a sample of the uranium-bearing mineral cleveite, and, upon investigating the gas produced by heating the sample, he found that a unique bright yellow line in its spectrum matched that of the D3 line observed in the spectrum of the Sun; the new element of helium was thus conclusively identified. In 1903 Ramsay and Frederick Soddy further determined that helium is a product of the spontaneous disintegration of radioactive substances.

Abundance and isotopes

Helium constitutes about 23 percent of the mass of the universe and is thus second in abundance to hydrogen in the cosmos. Helium is concentrated in stars, where it is synthesized from hydrogen by nuclear fusion. Although helium occurs in Earth’s atmosphere only to the extent of 1 part in 200,000 (0.0005 percent) and small amounts occur in radioactive minerals, meteoric iron, and mineral springs, great volumes of helium are found as a component (up to 7.6 percent) in natural gases in the United States (especially in Texas, New Mexico, Kansas, Oklahoma, Arizona, and Utah). Smaller supplies have been discovered in Algeria, Australia, Poland, Qatar, and Russia. Ordinary air contains about 5 parts per million of helium, and Earth’s⅘ crust is only about 8 parts per billion.

1 cylinder price approximately 30000