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25 Οκτ 2024 · Helium, chemical element, inert gas of Group 18 (noble gases) of the periodic table. The second lightest element, helium is a colorless, odorless, and tasteless gas that becomes liquid at -268.9 degrees Celsius. The boiling and freezing points of helium are lower than those of any other known substance.
Helium (from Greek: ἥλιος, romanized: helios, lit. 'sun') is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table.
Helium is a chemical element. Its official symbol is He, and its atomic number is 2, which means it has two protons in its nucleus. Helium was named after Helios – the Greek Titan of the Sun – because it was first observed when analysing sunlight during a solar eclipse in 1868.
After hydrogen, helium is the second most abundant element in the universe. It is present in all stars. It was, and is still being, formed from alpha-particle decay of radioactive elements in the Earth. Some of the helium formed escapes into the atmosphere, which contains about 5 parts per million by volume.
Helium (pronunciation: HEE-lee-em) is a colorless, odorless element classified as a non-metal, belonging to the group of inert gases in the periodic table and is represented by the chemical symbol He [1, 2, 3]. It is a monoatomic gas that forms weak diatomic molecules only at temperatures close to -273.15 °C or “the absolute zero” [4].
21 Νοε 2023 · Helium forms a compound when it reacts with other elements to form more complex gases and substances. It is the second element on the periodic table with the atomic...
Helium is the second most abundant element in the universe. Only hydrogen occurs more often than helium. Helium is also the second simplest of the chemical elements. Its atoms consist of two protons, two neutrons, and two electrons. Only the hydrogen atom is simpler than a helium atom.
