Properties Of 3He Isotope:
|Neutron Number (N)||1|
|Atomic Number / Proton Number (Z)||2|
|Mass Number / Nucleon Number (A)||3|
|Natural Abundance (%)||0.00000137|
|Atomic Mass (Da)||3.01602932|
|Relative Isotopic Mass||3.01602932|
|g-factor (g value)||-4.25499544|
|Electron Configuration Block||s|
|Melting Point (K)||0.95|
|Boiling Point (K)||4.216|
|Heat of Formation||―|
|Dipole Polarizability ||1.38375|
|Electron Affinity (kJ/mole)||-19.7|
|Electronegativity (Pauling scale)||―|
|Atomic Radius (pm)||―|
|Covalent Radius (pm)||―|
|VDW Radius (pm)||153|
Helium is a colourless, odourless gaseous nonmetallic element. It belongs to group 18 of the periodic table. This element has the lowest boiling point of all elements and can only be solidified under pressure. Within the eighteenth group, helium is on the second place in the earth's crust (after argon). Helium is chemically inert, no known compounds. It had been discovered within the sun spectrum in 1868 by Lockyer.
It is interesting to know the ending "um" (Helium) characteristic of metals was used in the element name as Lockier assumed that the element he discovered was a metal. By analogy with other noble gases, it would be logical to give him the name "Helion". In trendy science, the name "helion" is connected to the nucleus of the sunshine element atom helium-3.
Helium is named after the Greek Titan of the Sun, Helios.
Most of the earth's element nowadays is made by the natural disintegration of heavy radioactive parts (thorium and metal though there area unit different examples), since the alpha particles emitted by such decays area unit composed of helium-4 nuclei.
Helium is present in about 24% of the total mass of elements, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to that in both the Sun and Jupiter.
Earlier terrestrial helium was considered a non-renewable resource, because once in the atmosphere it easily disappears into space. However recent studies show that helium formed deep in the bowels of the earth as a result of radioactive decay can accumulate in reserves of natural gas in a larger than expected amount, in some cases released as a result of volcanic activity.
If electric current is passed through a tube filled with helium, discharges of various colors can be observed. The colors depend mainly on the gas pressure in the tube. Typically the visible light in the helium spectrum is yellow. If the pressure is reduced the color changes to pink, orange, yellow, bright yellow, yellow-green and green. The reason is in the presence of several series of lines in the helium spectrum located in the range between the infrared and ultraviolet parts of the spectrum.
Helium is used in balloons, deep sea diving and welding. Helium is additionally utilized in very low temperature research.
Helium is a convenient indicator for geologists. The location of deep faults can be determined on the surface of the Earth using helium imaging. Helium as a decay product of radioactive elements saturating the upper layer of the earth's crust seeps through cracks and rises into the atmosphere. Near such cracks, and especially at their intersections, the concentration of helium is higher. This phenomenon was first established by the Soviet geophysicist I.N. Yanitsky during a search for uranium ores. This pattern is used to study the deep structure of the Earth and to search for ores of non-ferrous and rare metals.
Leak detection is one of the industrial applications of helium. Since helium diffuses through solids three times faster than air, it is used as an indicator gas for detecting leaks in high-vacuum equipment (such as cryogenic tanks) and high-pressure containers. The object that is being tested is placed in a chamber. The chamber is then evacuated and filled with helium. Helium that escapes through leaks is detected by a sensitive device (helium mass spectrometer). The measurement procedure is called integrated helium testing and is usually automatic.
Helium mixtures, such as trimix, heliox and heliair, are used for deep immersion, since helium does not have narcotic properties as a breathing gas. Such mixtures reduce the effect of narcosis which intensifies with increasing depth. Respiratory gas density increases as pressure increases with depth. It is found that low molecular weight helium significantly reduces the effort of breathing by reducing the density of the mixture.
When mixed with a heavier gas such as xenon, helium is useful for thermoacoustic cooling due to its low Prandtl number and high heat capacity coefficient. Helium inertness has environmental benefits over conventional refrigeration systems, which contribute to global warming or depletion of the ozone layer.
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