Helium (He)
Helium is the 2nd element in the periodic table and has a symbol of He and atomic number of 2. It has an atomic weight of 4.00260 and a mass number of 4. Helium has two protons and two neutrons in its nucleus, and two electrons in one shell. It is located in group eighteen, period one and block s of the periodic table. Colourless, odourless gaseous nonmetallic element. Belongs to group 18 of the periodic table. Lowest boiling point of all elements and can only be solidified under pressure. Chemically inert, no known compounds. Discovered in the solar spectrum in 1868 by Lockyer.
| Atomic Number | 2 |
|---|---|
| Atomic Weight | 4.002602 |
| Mass Number | 4 |
| Group | 18 |
|---|---|
| Period | 1 |
| Block | s |
| Protons | 2 p+ |
|---|---|
| Neutrons | 2 n0 |
| Electrons | 2 e- |
Physical Properties
| Atomic Radius | 120 pm
|
|---|---|
| Molar Volume | 31.8 cm³/mol
|
| Covalent Radius | 46 pm
|
| Metallic Radius | |
| Ionic Radius | |
| Crystal Radius | |
| Van der Waals Radius |
140 pm
|
| Density | 0.000164 g/cm³
|
Chemical Properties
| Energy | |
|---|---|
| Proton Affinity | 177.8 kJ/mol
|
| Electron Affinity | -19.7 eV/particle
|
| Ionization Energy | 24.587387936 eV/particle
|
| Heat of Vaporization | 0.08 kJ/mol
|
| Heat of Fusion | |
| Heat of Formation | |
| Electrons | |
| Electron Shells | 2 |
 | |
| Valence Electrons | 2 ⓘ |
 | |
| Electron Configuration | 1s2ⓘ |
  | |
| Oxidation States | |
| Electronegativity | |
| Electrophilicity Index | 0.0674191963846371 eV/particle
|
| States of Matter | |
| Phase | Gas |
| Gas Phase | Monoatomic |
| Boiling Point | 4.222 K
|
| Melting Point | |
| Critical Pressure | 0.22746 MPa
|
| Critical Temperature | 5.195 K
|
| Triple Point | |
| Visual | |
Helium is a Colorless. He has a CPK of #ffc0cb, Jmol of #d9ffff, and MOLCAS GV of #d9ffff. The Appearance of Element 2 is colorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field. The Refractive Index of Helium (He) is 1.000035. | |
| Color | Colorless
|
| Appearance | colorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field |
| Refractive Index | 1.000035
|
| Thermodynamic Properties | |
| Thermal Conductivity | 0.152 W/(m K)
|
| Thermal Expansion | |
| Molar Heat Capacity | 20.786 J/(mol K)
|
| Specific Heat Capacity | 5.193 J/(g⋅K)
|
| Heat Capacity Ratio (Adiabatic Index) | 5/3 |
| Electrical Properties | |
| Type | |
| Electrical Conductivity | |
| Electrical Resistivity | |
| Superconducting Point | |
| Magnetism | |
| Type | diamagnetic |
| Magnetic Susceptibility (Mass) | -0.0000000059 m³/Kg
|
| Magnetic Susceptibility (Molar) | -0.0000000000236 m³/mol
|
| Magnetic Susceptibility (Volume) | -0.00000000105
|
| Magnetic Ordering | |
| Curie Point | |
| Neel Point | |
| Structure | |
The Crystal Structure of Helium is HEX. The lattice constant of He is 3.57 Å. The lattice angles of Element 2 are π/2, π/2, π/2. | |
| Crystal Structure | Face Centered Cubic (HEX) |
| Lattice Constant | 3.57 Å
|
| Lattice Angles | π/2, π/2, π/2 |
| Mechanical Properties | |
The Speed of Sound of Helium is 970 m/s. | |
| Hardness | |
| Bulk Modulus | |
| Shear Modulus | |
| Young's Modulus | |
| Poisson Ratio | |
| Speed of Sound | 970 m/s
|
| Classification | |
The CAS Group of Helium is VIII. The IUPAC Group of He is VIIIA. The Glawe Number of Element 2 is 1. The Mendeleev Number of Helium (He) is 112. The Pettifor Number of Helium is 1. The Geochemical Class of He is volatile. The Goldschmidt Class of Element 2 is atmophile. | |
| Category | Noble gases, Noble gases |
| CAS Group | VIII |
| IUPAC Group | VIIIA |
| Glawe Number | 1 |
| Mendeleev Number | 112 |
| Pettifor Number | 1 |
| Geochemical Class | volatile |
| Goldschmidt Class | atmophile |
Other
The Gas Basicity of Helium is 148.5 kJ/mol. The Dipole Polarizability of He is 1.38375 plus or minus 2.0E-5 a₀. Element 2 has a C6 Dispersion Coefficient (CD) of 1.42 a₀, and C6 Dispersion Coefficient (GB) of 1.47 a₀. The Allotropes of Helium (He) is . The Neutron Cross Section of Helium is 0.007. The Neutron Mass Absorption of He is 1.0E-5. The Quantum Numbers of Element 2 is 1S0. The Space Group of Helium (He) is 225 (Fm_3m).
Isotopes of Helium
| Stable Isotopes | 2 |
|---|---|
| Unstable Isotopes | 6 |
| Natural Isotopes | 2 |
3He
| Mass Number | 3 |
|---|---|
| Neutron Number | 1 |
| Relative Atomic Mass | |
| G-Factor | -4.25525062 ± 0.00000006
|
| Abundance | 0.0002 ± 0.0002
|
| Radioactivity | Stable |
| Half Life | Not Radioactive ☢️ |
| Spin | 1/2 |
| Quadrupole Moment | 0
|
| Discovery Year | 1934 |
| Parity | + |
4He
| Mass Number | 4 |
|---|---|
| Neutron Number | 2 |
| Relative Atomic Mass | |
| G-Factor | 0
|
| Abundance | 99.9998 ± 0.0002
|
| Radioactivity | Stable |
| Half Life | Not Radioactive ☢️ |
| Spin | 0 |
| Quadrupole Moment | 0
|
| Discovery Year | 1908 |
| Parity | + |
5He
| Mass Number | 5 |
|---|---|
| Neutron Number | 3 |
| Relative Atomic Mass | |
| G-Factor | |
| Abundance | |
| Radioactivity | ☢️ Radioactive |
| Half Life | 602 ± 22 ys
|
| Spin | 3/2 |
| Quadrupole Moment | |
| Discovery Year | 1937 |
| Parity | - |
| Decay Mode | Intensity |
|---|---|
| n (neutron emission) | 100% |
6He
| Mass Number | 6 |
|---|---|
| Neutron Number | 4 |
| Relative Atomic Mass | |
| G-Factor | 0
|
| Abundance | |
| Radioactivity | ☢️ Radioactive |
| Half Life | 806.92 ± 0.24 ms
|
| Spin | 0 |
| Quadrupole Moment | 0
|
| Discovery Year | 1936 |
| Parity | + |
| Decay Mode | Intensity |
|---|---|
| β− (β− decay) | 100% |
| β− d (β−-delayed deuteron emission) | 0.000278% |
7He
| Mass Number | 7 |
|---|---|
| Neutron Number | 5 |
| Relative Atomic Mass | |
| G-Factor | |
| Abundance | |
| Radioactivity | ☢️ Radioactive |
| Half Life | 2.51 ± 0.07 zs
|
| Spin | 3/2 |
| Quadrupole Moment | |
| Discovery Year | 1967 |
| Parity |
| Decay Mode | Intensity |
|---|---|
| n (neutron emission) | 100% |
8He
| Mass Number | 8 |
|---|---|
| Neutron Number | 6 |
| Relative Atomic Mass | |
| G-Factor | 0
|
| Abundance | |
| Radioactivity | ☢️ Radioactive |
| Half Life | 119.5 ± 1.5 ms
|
| Spin | 0 |
| Quadrupole Moment | 0
|
| Discovery Year | 1965 |
| Parity | + |
| Decay Mode | Intensity |
|---|---|
| β− (β− decay) | 100% |
| β− n (β−-delayed neutron emission) | 16% |
| β− t (β−-delayed triton emission) | 0.9% |
9He
| Mass Number | 9 |
|---|---|
| Neutron Number | 7 |
| Relative Atomic Mass | |
| G-Factor | |
| Abundance | |
| Radioactivity | ☢️ Radioactive |
| Half Life | 2.5 ± 2.3 zs
|
| Spin | 1/2 |
| Quadrupole Moment | 0
|
| Discovery Year | 1987 |
| Parity |
| Decay Mode | Intensity |
|---|---|
| n (neutron emission) | 100% |
10He
| Mass Number | 10 |
|---|---|
| Neutron Number | 8 |
| Relative Atomic Mass | |
| G-Factor | 0
|
| Abundance | |
| Radioactivity | ☢️ Radioactive |
| Half Life | 260 ± 40 ys
|
| Spin | 0 |
| Quadrupole Moment | 0
|
| Discovery Year | 1994 |
| Parity | + |
| Decay Mode | Intensity |
|---|---|
| 2n (2-neutron emission) | 100% |
History
French astronomer Jules Janssen obtained the first evidence of helium during the solar eclipse of 1868. Norman Lockyer and Edward Frankland suggested the name helium for the new element. In 1895, Sir William Ramsay discovered helium in the uranium mineral cleveite. It was independently discovered in cleveite by Per Teodor Cleve and Abraham Langlet. From the Greek word helios, the sun
| Discoverers | Sir William Ramsey, Nils Langet, P.T.Cleve |
|---|---|
| Discovery Location | Scotland/Sweden |
| Discovery Year | 1895 |
| Etymology (Name Origin) | Greek: hêlios (sun). |
| Pronunciation | HEE-li-em (English) |
Helium is not known to be toxic
Unlike any other element, helium will remain liquid down to absolute zero at normal pressures
Uses
Helium is used as a protective gas in growing silicon and germanium crystals, in titanium and zirconium production, and in gas chromatography. Helium at low temperatures is used in cryogenics. Helium is used for filling balloons and for pressurizing liquid fuel rockets. Helium is used as a shielding gas in arc welding processes. Used in balloons, deep sea diving & welding. Also used in very low temperature research.
Sources
Found in natural gas deposits & in the air (5 parts per billion) Constantly lost to space; replenished by radioactive decay (alpha particles).
| Abundance | |
|---|---|
| Abundance in Earth's crust | 0.008 mg/kg
|
| Natural Abundance (Oceans) | 0.000007 mg/L
|
| Natural Abundance (Human Body) | |
| Natural Abundance (Meteor) | |
| Natural Abundance (Sun) | 23 %
|
| Abundance in Universe | 23 %
|
Nuclear Screening Constants
| 1 | s | 0.3125 |
Also Known As
- He
- element 2
- 2He
Translations
- Italianelio
- Norwegian Bokmålhelium
- Frenchhélium
- GermanHelium
- Polishhel
- Esperantoheliumo
- Russianгелий
- Spanishhelio
- Dutchhelium
- Chinese (Traditional)氦
- Hebrewהליום
- AfrikaansHelium
- AragoneseHelio
- Arabicهيليوم
- Egyptian Arabicهيليوم
- AsturianHeliu
- AzerbaijaniHelium
- BelarusianГелій
- Bulgarianхелий
- Banglaহিলিয়াম
- BretonHeliom
- Bosnianhelij
- Catalanheli
- CherokeeᎦᏌᎧᎯᎨ ᎤᏃᎴ
- Central Kurdishھیلیۆم
- CorsicanEliu
- Czechhelium
- ChuvashГели
- WelshHeliwm
- Danishhelium
- Greekήλιο
- EstonianHeelium
- Basquehelio
- Persianهلیوم
- Finnishhelium
- FaroeseHelium
- Northern FrisianHelium
- FriulianEli
- Western Frisianhelium
- Irishhéiliam
- Galicianhelio
- GuaraniTataveve
- Gujaratiહીલિયમ
- ManxHailium
- Hakka ChineseHoi
- HawaiianHiliuma
- Hindiहीलियम
- Fiji HindiHelium
- CroatianHelij
- Upper Sorbianhelium
- Haitian CreoleElyòm
- Hungarianhélium
- Armenianհելիում
- Interlinguahelium
- Indonesianhelium
- Ilokohelio
- Idohelio
- Icelandichelín
- Japaneseヘリウム
- Lojbansolnavni
- JavaneseHelium
- Georgianჰელიუმი
- KazakhГелий
- Kannadaಹೀಲಿಯಮ್
- Korean헬륨
- Komi-PermyakГелий
- ColognianHelium
- KurdishHelyûm
- KomiГелий
- Latinhelium
- LuxembourgishHelium
- LimburgishHelium
- LigurianElio
- LombardEli
- LingalaEliyúmu
- LithuanianHelis
- Latvianhēlijs
- Māorihaumāmā
- Macedonianхелиум
- Malayalamഹീലിയം
- Marathiहेलियम
- Western MariГелий
- Malayhelium
- Burmeseဟီလီယမ်
- nahTōnatiuyoh
- Low GermanHelium
- Nepaliहेलियम
- Newariहिलियम
- Norwegian Nynorskhelium
- Novialhelium
- NavajoNíłchʼi Ászólí
- OccitanÈli
- Punjabiਹੀਲਿਆਮ
- PapiamentoHelium
- PiedmonteseElio
- Western Panjabiہیلیم
- PonticΉλιον
- Portuguesehélio
- QuechuaIlyu
- Romanianheliu
- Sanskritहीलियम्
- Serbo-CroatianHelij
- Sinhalaහීලියම්
- Slovakhélium
- Slovenianhelij
- AlbanianHeliumi
- Serbianхелијум
- Saterland FrisianHelium
- SundaneseHélium
- Swedishhelium
- SwahiliHeli
- Tamilஈலியம்
- Teluguహీలియం
- Tajikгелий
- Thaiฮีเลียม
- TagalogHelyo
- TurkishHelyum
- Uyghurگېلىي
- Ukrainianгелій
- Urduشمصر
- UzbekGeliy
- VepsGelii
- Vietnameseheli
- West FlemishHelium
- WarayHelyo
- KalmykГелион
- Yiddishהעליום
- YorubaHílíọ̀m
- Chinese氦
- English (United Kingdom)helium
- German (Switzerland)Helium
- English (Canada)Helium
- Portuguese (Brazil)hélio
- Cantonese氦
- Amharicሒሊየም
- CebuanoHelyo
- Odiaହିଲିୟମ
- ScotsHelium
- Sicilianeliu
- emlÊli
- KikuyuHelium
- YakutГелий
- Chinese (Hong Kong SAR China)氦
- Chinese (China)氦
- Chinese (Simplified)氦
- BashkirГелий
- SomaliHiliyaam
- Literary Chinese氦
- Belarusian (Taraskievica orthography)гель
- SamogitianHelis
- Min Nan ChineseHe
- AromanianHeliu
- cdoHâi
- Scottish GaelicHelium
- TuvinianГелий
- Malteseelju
- Church SlavicХєлїи
- Paliहेलियम
- Gan Chinese氦
- Mongolianгели
- azbهلیوم
- Tibetanཧེ་རླུང་།
- Bhojpuriहीलियम
- Jamaican Creole EnglishIiliom
- Khmerអេលីយ៉ូម
- Lingua Franca Novaelio
- Tatarгелий
- Tatar (Cyrillic)гелий
- Wu Chinese氦
- oloHelium
- KyrgyzГелий
- ShonaHelium
- kbpHeelim
- Assameseহিলিয়াম
- Mingrelianჰელიუმი
- Chinese (Taiwan)氦
- Santaliᱦᱤᱞᱤᱭᱟᱢ
- SardinianÈliu
- RusynГелий
- Chinese (Singapore)氦
- Chinese (Malaysia)氦
- Chinese (Macao SAR China)氦
- Moroccan Arabicهيليوم
- Pashtoهېليوم
- lldElie
- BikolElyo
- CornishHeliom
- Manipuriꯍꯤꯂꯤꯌꯝ
- BalineseHélium
- WalloonEliom
- Inari SamiHelium
- Malay (Arabic)هيليوم
- TachelhitAhilyum
- BuriatГели
- Awadhiहेलियम
- GandaKeriyaamu
- Sindhiهيليئم
- blkဟီလီယမ်
- Korean (North Korea)헬리움
- ZuluIHwelanga
- OromoHeeliyeemii
