Helium

Helium (He)

He
Atomic Number2
Atomic Weight4.002602
Massagetal4
Group18
Period1
Blocks
proton2 p+
neutron2 n0
elektron2 e-
Animated Bohr model of He (Helium)

Physical Property

Atoomradius
120 pm
molar volume
Covalent Radius
46 pm
Metallic Radius
Ioonradius
Crystal Radius
Van der Waals radius
140 pm
density
0,000164 g/cm³
Atomic Radii Of The Elements: Helium0102030405060708090100110120130140pmAtoomradiusCovalent RadiusMetallic RadiusVan der Waals radius

Chemical Property

energie
proton affinity
177,8 kJ/mol
electron affinity
ionization energy
24,587387936 eV/particle
ionization energy of He (Helium)
Verdampingswarmte
0,08 kJ/mol
smeltingswarmte
Vormingsentalpie
elektron
Elektronskil2
Bohr model: He (Helium)
Valenselektrone2
Lewisteorie: He (Helium)
elektronkonfigurasie1s2
Enhanced Bohr model of He (Helium)
Orbital Diagram of He (Helium)
Oksidasietoestand
Elektronegatiwiteit
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
kleur
Colorless
appearancecolorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field
Brekingsindeks
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
Geleidingsvermoë
Elektriese resistiwiteit
superconductivity
Magnetisme
typediamagnetic
magnetic susceptibility (Mass)
-0,0000000059 m³/Kg
magnetic susceptibility (Molar)
-0,0000000000236 m³/mol
magnetic susceptibility (Volume)
-0,00000000105
magnetic ordering
Curie temperature
Néel temperature
structure
Crystal StructureFace Centered Cubic (HEX)
lattice constant
3,57 Å
Lattice Anglesπ/2, π/2, π/2
mechanical property
hardness
Massamodulus
Skuifmodulus
Young se modulus
Poisson se verhouding
Spoed van klank
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
Ruimtegroep225 (Fm_3m)

Isotopes of Helium

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

3He

Massagetal3
neutron number1
relative atomic mass
3,01602932197 ± 0,00000000006 Da
g-factor
-4,25525062 ± 0,00000006
natural abundance
0,0002 ± 0,0002
radioaktiwiteitStabiele isotoop
HalfleeftydNot Radioactive ☢️
spin1/2
nuclear quadrupole moment
0
ontdekkingsdatum1934
parity+

4He

Massagetal4
neutron number2
relative atomic mass
4,00260325413 ± 0,00000000016 Da
g-factor
0
natural abundance
99,9998 ± 0,0002
radioaktiwiteitStabiele isotoop
HalfleeftydNot Radioactive ☢️
spin0
nuclear quadrupole moment
0
ontdekkingsdatum1908
parity+

5He

Massagetal5
neutron number3
relative atomic mass
5,012057224 ± 0,00002147 Da
g-factor
natural abundance
radioaktiwiteit☢️ radioactive element
Halfleeftyd
602 ± 22 ys
spin3/2
nuclear quadrupole moment
ontdekkingsdatum1937
parity-

decay modeintensity
n (neutron emission)100%

6He

Massagetal6
neutron number4
relative atomic mass
6,018885889 ± 0,000000057 Da
g-factor
0
natural abundance
radioaktiwiteit☢️ radioactive element
Halfleeftyd
806,92 ± 0,24 ms
spin0
nuclear quadrupole moment
0
ontdekkingsdatum1936
parity+

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

7He

Massagetal7
neutron number5
relative atomic mass
7,027990652 ± 0,000008115 Da
g-factor
natural abundance
radioaktiwiteit☢️ radioactive element
Halfleeftyd
2,51 ± 0,07 zs
spin3/2
nuclear quadrupole moment
ontdekkingsdatum1967
parity

decay modeintensity
n (neutron emission)100%

8He

Massagetal8
neutron number6
relative atomic mass
8,033934388 ± 0,000000095 Da
g-factor
0
natural abundance
radioaktiwiteit☢️ radioactive element
Halfleeftyd
119,5 ± 1,5 ms
spin0
nuclear quadrupole moment
0
ontdekkingsdatum1965
parity+

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

9He

Massagetal9
neutron number7
relative atomic mass
9,043946414 ± 0,000050259 Da
g-factor
natural abundance
radioaktiwiteit☢️ radioactive element
Halfleeftyd
2,5 ± 2,3 zs
spin1/2
nuclear quadrupole moment
0
ontdekkingsdatum1987
parity

decay modeintensity
n (neutron emission)100%

10He

Massagetal10
neutron number8
relative atomic mass
10,052815306 ± 0,000099676 Da
g-factor
0
natural abundance
radioaktiwiteit☢️ radioactive element
Halfleeftyd
260 ± 40 ys
spin0
nuclear quadrupole moment
0
ontdekkingsdatum1994
parity+

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

geskiedenis

Ontdek deurSir William Ramsey, Nils Langet, P.T.Cleve
ligging van ontdekkingScotland/Sweden
ontdekkingsdatum1895
etimologieGreek: hêlios (sun).
uitspraakHEE-li-em (Engels)

source

Abundance
Abundance in Earth's crust
0,008 mg/kg
natural abundance (oseaan)
0,000007 mg/L
natural abundance (human body)
natural abundance (Meteoroïde)
natural abundance (Son)
23 %
Abundance in Universe
23 %

Nuclear Screening Constants

1s0.3125