Hílíọ̀mù, Hélíọ̀m, tabi Helium (pípè /ˈhiːliəmu/, HEE-lee-əm) ni ẹ́límẹ̀ntì kẹ́míkà tó ní nọ́mbà átọ́mù 2 àti iwuwo atomu to je 4.002602, àmì ìdámọ̀ rẹ̀ ni He. O je efuufu oniatomukan, alaigbera, aláìláwọ̀, alailoorun, alainitowo, ati alailewu to siwaju ẹgbẹ́ ẹ̀fúùfù abíire ninu tabili asiko. Awon ojuami ìhó àti ìyọ́ rẹ̀ je awon ti won kerejulo larin awon ẹ́límẹ̀ntì, o si wa pere gege bi efuufu ayafi nigba to ba wa nipo lounloun. Leyin hydrogen, ohun ni elimenti keji to pojulo ni agbalaaye, o si je bi 24% gbogbo akojo elimenti ninu galaksi wa.

Hílíọ̀mù, 2He
Àdàkọ:Infobox element/symbol-to-top-image/alt
Hílíọ̀mù
Pípè /ˈhliəm/ (HEE-lee-əm)
Ìhànsójúẹ̀fúùfù aláìláwọ̀, yíò tan àwọ̀ ọsàn-pupa tó bá wà nínú pápá ìtanna ìtiná gíga
Ìwúwo átọ̀mù Ar, std(He)4.002602(2)Àdàkọ:CIAAW2013
nọ́mbà ìsújọHe:
Hílíọ̀mù ní orí tábìlì àyè
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
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He

Ne
háídrójìnhílíọ̀mùlítíọ̀mù
Nọ́mbà átọ̀mù (Z)2
Ẹgbẹ́group 18 (noble gases)
Àyèàyè 1
Àdìpọ̀Àdìpọ̀-s
Ẹ̀ka ẹ́límẹ́ntìÀdàkọ:Infobox element/category format
Ìtò ẹ̀lẹ́ktrọ́nùÀdàkọ:Infobox element/symbol-to-electron-configuration
Iye ẹ̀lẹ́ktrọ́nù lórí ìpele kọ̀ọ̀kan2
Àwọn ohun ìní ara
Ìfarahàn at STPẹ̀fúùfù
Ìgbà ìyọ́(at 2.5 MPa) 0.95 K ​(−272.20 °C, ​−457.96 °F)
Ígbà ìhó4.22 K ​(−268.93 °C, ​−452.07 °F)
Kíki (at STP)0.1786 g/L
when liquid (at m.p.)0.145 g/cm3
when liquid (at b.p.)0.125 g/cm3
Critical point5.19 K, 0.227 MPa
Heat of fusion0.0138 kJ/mol
Heat of 0.0829 kJ/mol
Molar heat capacity5R/2 = 20.786 J/(mol·K)
 pressure (defined by ITS-90)
Atomic properties
Oxidation statesÀdàkọ:Infobox element/symbol-to-oxidation-state
ElectronegativityPauling scale: no data
Covalent radius28 pm
Van der Waals radius140 pm
Àdàkọ:Infobox element/spectral lines
Other properties
Natural occurrenceÀdàkọ:Infobox element/symbol-to-occurrence
Crystal structureÀdàkọ:Infobox element/crystal structure
Speed of sound972 m/s
Thermal conductivity0.1513 W/(m·K)
Magnetic orderingdiamagnetic[1]
CAS Number7440-59-7
History
DiscoveryPierre Janssen, Norman Lockyer (1868)
First isolationWilliam Ramsay, Per Teodor Cleve, Abraham Langlet (1895)
Main isotopes of hílíọ̀mù
Àdàkọ:Infobox element/isotopes table
  • Atmospheric value, abundance may differ elsewhere.
Àdàkọ:Category-inline
| references



ItumosiÀtúnṣe

  1. Magnetic susceptibility of the elements and inorganic compounds, in Handbook of Chemistry and Physics 81st edition, CRC press.