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Noble gas is translated from the German noun Edelgas, first used in 1900 by Hugo Erdmann [ 5 ] to indicate their extremely low level of reactivity. The name makes an analogy to the term " noble metals ", which also have low reactivity. The noble gases have also been referred to as inert gases, but this label is deprecated as many noble gas ...
On the periodic table of the elements it is a p-block element, a member of group 18 and the last member of period 7. Its only known isotope, oganesson-294 , is highly radioactive , with a half-life of 0.7 ms and, as of 2020, [update] only five atoms have been successfully produced. [ 19 ]
The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods ") and columns (" groups "). It is an icon of chemistry and is widely used in physics and other sciences. It is a depiction of the periodic law, which states that when the elements are arranged in order ...
People. Chemical elements are sometimes named after people, especially the synthetic elements discovered (created) after c. 1940. Very few are named after their discoverers, and only two have been named after living people: the element seaborgium was named after Glenn Seaborg, who was alive at the time of naming in 1997; [5] and in 2016 ...
41 of the 118 known elements have names associated with, or specifically named for, places around the world or among astronomical objects. 32 of these have names tied to the places on Earth, and the other nine are named after to Solar System objects: helium for the Sun; tellurium for the Earth; selenium for the Moon; mercury (indirectly), uranium, neptunium and plutonium after their respective ...
118 chemical elements have been identified and named officially by IUPAC. A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ]
Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. [9] Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abundant as water vapor (which averages about 4000 ppmv, but varies greatly), 23 times as abundant as ...
Helium. hexagonal close-packed (hcp) 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.