Àdàkọ:Infobox helium

hydrogen ← helium → lithium - ↑ He ↓ Ne 2He Periodic table
Ìfarahàn
Colorless gas, exhibiting a purple glow when placed in a high voltage electric field Spectral lines of Helium.
Àwọn ìní àníkárí
Orúkọ, àmì-ìdámọ̀, nọ́mbà	helium, He, 2
Ìpè	/ˈhiːliəm/ HEE-lee-əm
Ẹ̀ka apilẹ̀sẹ̀	noble gases
Àdìpọ̀, ìgbà, block	18, 1, s
Ìwúwo átọ́mù	4.002602(2) g·mol−1
Ìtòjọ ẹ̀lẹ́ktrónì	1s2
Àwọn ẹ̀lẹ́ktrónì lórí ọ̀nà kan	2 (Image)
Àwọn ìní aláfójúrí
Phase	gas
Kíki	(0 °C, 101.325 kPa) 0.1786 g/L
ojúàmì ìyọ́	(at 2.5 MPa) 0.95 K, −272.20 °C, −457.96 °F
ajúàmì ìhó	4.22 K, −268.93 °C, −452.07 °F
Critical point	5.19 K, 0.227 MPa
Heat of fusion	0.0138 kJ·mol−1
Heat of vaporization	0.0829 kJ·mol−1
Specific heat capacity	(25 °C) 20.786 J·mol−1·K−1
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
Electronegativity	no data (Pauling scale)
Ionization energies	1st: 2372.3 kJ·mol−1
	2nd: 5250.5 kJ·mol−1
Covalent radius	28 pm
Van der Waals radius	140 pm
Miscellanea
Crystal structure	hexagonal close-packed
Magnetic ordering	diamagnetic
Thermal conductivity	(300 K) 0.1513 W·m−1·K−1
Speed of sound	972 m/s
CAS registry number	7440-59-7
Most stable isotopes
Main article: Isotopes of helium
iso NA half-life DM DE (MeV) DP 3He 0.000137%* 3He is stable with 1 neutron 4He 99.999863%* 4He is stable with 2 neutrons *Atmospheric value, abundance may differ elsewhere.

References

This reference list does not appear in the article.