A Detailed Sketch About Helium

Group 18 of the Periodic Table contains the chemical element helium (He), which is an inert gas (noble gasses). Helium is the second lightest element (only hydrogen is lighter), and it is a colorless, odorless, and tasteless gas that turns into a liquid at a temperature of 268.9 degrees Celsius (452 degrees Fahrenheit). Helium has lower boiling and freezing points than any other known substance, making it the most energy-dense element. Helium is the only element that cannot be solidified by sufficient cooling under normal atmospheric pressure; it requires the application of 25 atmospheres of pressure at a temperature of 1 K (272 degrees Celsius or 458 degrees Fahrenheit) in order to convert it to its solid state.

History

It was the French astronomer Pierre Janssen who discovered helium in the solar chromosphere in 1868 while observing a bright yellow line in the solar chromosphere during an eclipse that led to the element’s discovery in the gaseous atmosphere surrounding the Sun. Initially, it was thought that this line represented the element sodium, but it was later discovered that it represented the element helium.It was also in that same year that the English astronomer Joseph Norman Lockyer discovered a yellow line in the solar spectrum that did not correspond to the previously known sodium D1 and D2 lines, which he named the D3 line after himself. After concluding that the D3 line was caused by an element in the Sun that had previously been unknown on Earth, Lockyer and chemist Edward Frankland named the element hlios after the Greek word for sun, which means “sun.” In 1895, the British chemist Sir William Ramsay made the discovery of the presence of helium on the planet Earth. Using a sample of cleveite, Ramsay discovered that a unique bright yellow line in its spectrum matched that of the D3 line observed in the spectrum of the Sun, conclusively establishing helium as a new element. Ramsay’s discovery was made possible by the discovery that the new element helium was produced by heating cleveite.

The Abundance of Elements And The Isotopes

Helium makes up approximately 23 percent of the universe’s mass and is therefore the second most abundant element in the universe after hydrogen. In stars, where it is produced by nuclear fusion, helium concentrations are high because it is a rare and valuable element. Although helium is found in trace amounts in the Earth’s atmosphere (one part in 200,000, or 0.0005 percent) and in trace amounts in radioactive minerals, meteoric iron, and mineral springs, large quantities of helium are found as a component (up to 7.6 percent) in natural gases in the United States, where it is found in large quantities (especially in Texas, New Mexico, Kansas, Oklahoma, Arizona, and Utah). Smaller supplies have been discovered in Algeria, Australia, Poland, Qatar, and Russia, amongst other places. Helium is present in only about 5 parts per million of ordinary air, and it is only about 8 parts per billion in the Earth’s crust. Despite the fact that the nucleus of every helium atom contains two protons, there are isotopes of helium, as is the case with all other elements. Due to the fact that the known helium isotopes contain between one and six neutrons, their mass numbers range from three to eight.

Properties

Helium-4 is unique in that it exists in both liquid and gaseous forms. The normal liquid form of helium is referred to as helium I, and it can be found at temperatures ranging from its boiling point of 4.21 K (268.9 °C) down to approximately 2.18 K (271 °C). Thermal conductivity of helium-4 increases to more than 1,000 times greater than that of copper when the temperature is below 2.18 K. This liquid form of helium is referred to as helium II in order to distinguish it from the more common liquid helium IN. helium II possesses a property known as superfluidity, which means that its viscosity, or resistance to flow, is so low that it has not yet been determined. This liquid forms a thin film on the surface of any substance it comes into contact with, and this film flows without friction even when the force of gravity is exerted against it. Helium-3, on the other hand, is a rarer element that can be divided into three distinct liquid phases, two of which are superfluids. A superfluid state of helium-4 was discovered by the Russian scientist Pyotr Leonidovich Kapitsa in the mid-1930s, and the same phenomenon in helium-3 was discovered by Douglas D. Osheroff, David M. Lee, and Robert C. Richardson of the United States in 1972, and it has since been confirmed by other researchers. An isotope mixture of the helium-3 and the helium-4 isotopes separates into two layers at temperatures below about 0.8 K (272.4 degrees Celsius or 458.2 degrees Fahrenheit). One layer is almost completely composed of helium-3, while the other is mostly composed of helium-4 but retains approximately 6 percent helium-3 even at the lowest temperatures achieved.

Production and Applications

In order to separate helium gas (98.2 percent pure) from natural gas, the other components must be liquefied at extremely low temperatures and under extremely high pressures. In the presence of other gasses, adsorption on cooled, activated charcoal results in the production of 99.995 percent pure helium. Several kilogrammes of helium are produced by large-scale liquefaction of air; the amount of helium produced from 1,000 tonnes (900 metric tonnes) of air is approximately 112 cubic feet (3.17 cubic meters), when measured at room temperature and normal atmospheric pressure.

Conclusion

Group 18 of the Periodic Table contains the chemical element helium (He), which is an inert gas (noble gasses). Helium is the second lightest element (only hydrogen is lighter), and it is a colorless, odorless, and tasteless gas that turns into a liquid at a temperature of 268.9 degrees Celsius (452 degrees Fahrenheit).It was the French astronomer Pierre Janssen who discovered helium in the solar chromosphere in 1868 while observing a bright yellow line in the solar chromosphere during an eclipse that led to the element’s discovery in the gaseous atmosphere surrounding the Sun.Helium makes up approximately 23 percent of the universe’s mass and is therefore the second most abundant element in the universe after hydrogen.In order to separate helium gas (98.2 percent pure) from natural gas, the other components must be liquefied at extremely low temperatures and under extremely high pressures.