Hêlyûm

Hêlyûm (He)

chemical element with symbol He and atomic number 2; rare gas
Atomic Number2
Atomic Weight4.002602
Hejmara baristeyî4
Group18
Period1
Blocks
Proton2 p+
Notron2 n0
Kareva2 e-
Animated Bohr model of He (Hêlyûm)

Physical Property

Atomic Radius
120 pm
molar volume
Covalent Radius
46 pm
Metallic Radius
ionic radius
Crystal Radius
Van der Waals radius
140 pm
density
0,000164 g/cm³
Atomic Radii Of The Elements: Hêlyûm0102030405060708090100110120130140pmAtomic RadiusCovalent RadiusMetallic RadiusVan der Waals radius

Chemical Property

wize
proton affinity
177,8 kJ/mol
electron affinity
ionization energy
24,587387936 eV/particle
ionization energy of He (Hêlyûm)
enthalpy of vaporization
0,08 kJ/mol
enthalpy of fusion
standard enthalpy of formation
Kareva
electron shell2
Bohr model: He (Hêlyûm)
valence electron2
Lewis structure: He (Hêlyûm)
electron configuration1s2
Enhanced Bohr model of He (Hêlyûm)
Orbital Diagram of He (Hêlyûm)
oxidation number
electronegativity
Electrophilicity Index
0,0674191963846371 eV/particle
fundamental state of matter
phase of matterGas
gaseous state of matterMonoatomic
Boiling Point
4,222 K
Melting Point
critical pressure
0,22746 MPa
critical temperature
5,195 K
triple point
2,177 K
5,043 kPa
appearance
color
Colorless
appearancecolorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field
refractive index
1,000035
thermodynamic material property
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 ratio5/3
electrical properties
type
electrical conductivity
electrical resistivity
superconductivity
magnetism
typediamagnetic
magnetic susceptibility (Mass)
-0,0000000059 m³/Kg
magnetic susceptibility (Molar)
-0,0000000000236 m³/mol
magnetic susceptibility (Volume)
-0,00000000105
magnetic ordering
Germahiya Curie
Néel temperature
pêkhate
Crystal StructureFace Centered Cubic (HEX)
lattice constant
3,57 Å
Lattice Anglesπ/2, π/2, π/2
mechanical property
hardness
bulk modulus
shear modulus
Young's modulus
Poisson's ratio
Leza dengê
970 m/s
classification
CategoryNoble gases, Noble gases
CAS GroupVIII
IUPAC GroupVIIIA
Glawe Number1
Mendeleev Number112
Pettifor Number1
Geochemical Classvolatile
Goldschmidt classificationatmophile

other

Gas Basicity
148,5 kJ/mol
polarizability
1,38375 ± 0,00002 a₀
C6 Dispersion Coefficient
1,42 a₀
allotrope
Neutron cross section
0,007
Neutron Mass Absorption
0,00001
quantum number1S0
space group225 (Fm_3m)

Isotopes of Helium

Stable Isotopes2
Unstable Isotopes6
Natural Isotopes2
Isotopic Composition4100.00%4100.00%30.00%30.00%

3He

Hejmara baristeyî3
neutron number1
Giraniya atomê
3,01602932197 ± 0,00000000006 Da
g-factor
-4,25525062 ± 0,00000006
natural abundance
0,0002 ± 0,0002
radioactivitystable isotope
half-lifeNot Radioactive ☢️
spin1/2
nuclear quadrupole moment
0
dema îcadkirinê yan keşfê1934
parity+

4He

Hejmara baristeyî4
neutron number2
Giraniya atomê
4,00260325413 ± 0,00000000016 Da
g-factor
0
natural abundance
99,9998 ± 0,0002
radioactivitystable isotope
half-lifeNot Radioactive ☢️
spin0
nuclear quadrupole moment
0
dema îcadkirinê yan keşfê1908
parity+

5He

Hejmara baristeyî5
neutron number3
Giraniya atomê
5,012057224 ± 0,00002147 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
602 ± 22 ys
spin3/2
nuclear quadrupole moment
dema îcadkirinê yan keşfê1937
parity-

decay modeintensity
n (neutron emission)100%

6He

Hejmara baristeyî6
neutron number4
Giraniya atomê
6,018885889 ± 0,000000057 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
806,92 ± 0,24 ms
spin0
nuclear quadrupole moment
0
dema îcadkirinê yan keşfê1936
parity+

decay modeintensity
β (β decay)100%
β d (β-delayed deuteron emission)0.000278%

7He

Hejmara baristeyî7
neutron number5
Giraniya atomê
7,027990652 ± 0,000008115 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
2,51 ± 0,07 zs
spin3/2
nuclear quadrupole moment
dema îcadkirinê yan keşfê1967
parity

decay modeintensity
n (neutron emission)100%

8He

Hejmara baristeyî8
neutron number6
Giraniya atomê
8,033934388 ± 0,000000095 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
119,5 ± 1,5 ms
spin0
nuclear quadrupole moment
0
dema îcadkirinê yan keşfê1965
parity+

decay modeintensity
β (β decay)100%
β n (β-delayed neutron emission)16%
β t (β-delayed triton emission)0.9%

9He

Hejmara baristeyî9
neutron number7
Giraniya atomê
9,043946414 ± 0,000050259 Da
g-factor
natural abundance
radioactivity☢️ radioactive element
half-life
2,5 ± 2,3 zs
spin1/2
nuclear quadrupole moment
0
dema îcadkirinê yan keşfê1987
parity

decay modeintensity
n (neutron emission)100%

10He

Hejmara baristeyî10
neutron number8
Giraniya atomê
10,052815306 ± 0,000099676 Da
g-factor
0
natural abundance
radioactivity☢️ radioactive element
half-life
260 ± 40 ys
spin0
nuclear quadrupole moment
0
dema îcadkirinê yan keşfê1994
parity+

decay modeintensity
2n (2-neutron emission)100%
Helium discharge tube

dîrok

kaşîf an îcadkerSir William Ramsey, Nils Langet, P.T.Cleve
location of discoveryScotland/Sweden
dema îcadkirinê yan keşfê1895
BêjenasîGreek: hêlios (sun).
pronunciationHEE-li-em (îngilîzî)

source

Abundance
Abundance in Earth's crust
0,008 mg/kg
natural abundance (Okyanûs)
0,000007 mg/L
natural abundance (human body)
natural abundance (meteoroid)
natural abundance (Roj)
23 %
Abundance in Universe
23 %

Nuclear Screening Constants

1s0.3125