ഫലകം:Infobox ഹീലിയം

ഹീലിയം, ₂He

ഹീലിയം
Pronunciation	/ˈhiːliəm/ ​(HEE-lee-əm)
Appearance	നിറമില്ല
Standard atomic weight Ar, std(He)	4.002602(2)
ഹീലിയം in the periodic table
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 - ↑ He ↓ Ne ഹൈഡ്രജൻ ← ഹീലിയം → ലിഥിയം
Atomic number (Z)	2
Group	group 18 (noble gases)
Period	period 1
Block	s-block
Element category	Noble gas
Electron configuration	1s2
Electrons per shell	2
Physical properties
Phase at STP	gas
Melting point	(at 2.5 MPa) 0.95 K ​(−272.2 °C, ​−458.0 °F)
Boiling point	4.22 K ​(−268.93 °C, ​−452.07 °F)
Density (at STP)	0.1786 g/L
Critical point	5.19 K, 0.227 MPa
Heat of fusion	0.0138 kJ/mol
Heat of vaporization	0.0829 kJ/mol
Molar heat capacity	20.786 J/(mol·K)
Vapor pressure (defined by ITS-90) P (Pa) 1 10 100 1 k 10 k 100 k at T (K)     1.23 1.67 2.48 4.21
Atomic properties
Oxidation states	0
Electronegativity	Pauling scale: no data
Atomic radius	calculated: 31 pm
Covalent radius	32 pm
Van der Waals radius	140 pm
Spectral lines of ഹീലിയം
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp)
Thermal expansion	{ µm/(m·K) (at 25 °C)
Thermal conductivity	0.1513  W/(m·K)
CAS Number	7440-59-7
Main isotopes of ഹീലിയം
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct 3He 0.000137%* stable 4He 99.999863%* stable
Atmospheric value, abundance may differ elsewhere.

He data m.p. cat
	in	calc from C	diff	report	ref
C	−272.2	—	—
K	2.5	0.950
F	−458.0	−457.960
WD	-272.05 സെൽഷ്യസ്
input	C: −272.2, K: (at 2.5 MPa) 0.95, F: −458.0
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He data b.p. cat
	in	calc from C	diff	report	ref
C	−268.93	—	—
K	4.22	4.22
F	−452.07	−452.07
WD	-268.9 സെൽഷ്യസ്
input	C: −268.93, K: 4.22, F: −452.07
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