Eli

Eli (He)

chemical element with symbol He and atomic number 2; rare gas
Atomic Number2
Atomic Weight4.002602
mass number4
Group18
Period1
Blocks
proton2 p+
neutron2 n0
electron2 e-
Animated Bohr model of He (Eli)

Proprietat Fisica

Rai Atomic
120 pm
molar volume
covalent radius
46 pm
Metallic Radius
ionic radius
Crystal Radius
Rai de van der Waals
140 pm
densitat
0.000164 g/cm³
Atomic Radii Of The Elements: Eli0102030405060708090100110120130140pmRai AtomicCovalent RadiusMetallic RadiusRai de van der Waals

Chemical Property

energia
proton affinity
177.8 kJ/mol
electron affinity
ionization energy
24.587387936 eV/particle
ionization energy of He (Eli)
enthalpy of vaporization
0.08 kJ/mol
enthalpy of fusion
standard enthalpy of formation
electron
electron shell2
Bohr model: He (Eli)
valence electron2
Lewis structure: He (Eli)
electron configuration1s2
Enhanced Bohr model of He (Eli)
Orbital Diagram of He (Eli)
oxidation number
Electronegativitat
Electrophilicity Index
0.0674191963846371 eV/particle
fundamental state of matter
estat de la matèriaGas
gaseous state of matterMonoatomic
Boiling Point
4.222 K
Melting Point
critical pressure
0.22746 MPa
critical temperature
5.195 K
Ponch triple
2.177 K
5.043 kPa
appearance
Color
Colorless
appearancecolorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field
Indici de refraccion
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
Curie temperature
Néel temperature
estructura
Crystal StructureFace Centered Cubic (HEX)
lattice constant
3.57 Å
Lattice Anglesπ/2, π/2, π/2
mechanical property
Duretat
bulk modulus
shear modulus
Young's modulus
Poisson's ratio
speed of sound
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

mass number3
neutron number1
relative atomic mass
3.01602932197 ± 0.00000000006 Da
g-factor
-4.25525062 ± 0.00000006
natural abundance
0.0002 ± 0.0002
Radioactivitatstable isotope
SemividaNot Radioactive ☢️
Espin1/2
nuclear quadrupole moment
0
data de descobèrta1934
parity+

4He

mass number4
neutron number2
relative atomic mass
4.00260325413 ± 0.00000000016 Da
g-factor
0
natural abundance
99.9998 ± 0.0002
Radioactivitatstable isotope
SemividaNot Radioactive ☢️
Espin0
nuclear quadrupole moment
0
data de descobèrta1908
parity+

5He

mass number5
neutron number3
relative atomic mass
5.012057224 ± 0.00002147 Da
g-factor
natural abundance
Radioactivitat☢️ radioactive element
Semivida
602 ± 22 ys
Espin3/2
nuclear quadrupole moment
data de descobèrta1937
parity-

decay modeintensity
n (neutron emission)100%

6He

mass number6
neutron number4
relative atomic mass
6.018885889 ± 0.000000057 Da
g-factor
0
natural abundance
Radioactivitat☢️ radioactive element
Semivida
806.92 ± 0.24 ms
Espin0
nuclear quadrupole moment
0
data de descobèrta1936
parity+

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

7He

mass number7
neutron number5
relative atomic mass
7.027990652 ± 0.000008115 Da
g-factor
natural abundance
Radioactivitat☢️ radioactive element
Semivida
2.51 ± 0.07 zs
Espin3/2
nuclear quadrupole moment
data de descobèrta1967
parity

decay modeintensity
n (neutron emission)100%

8He

mass number8
neutron number6
relative atomic mass
8.033934388 ± 0.000000095 Da
g-factor
0
natural abundance
Radioactivitat☢️ radioactive element
Semivida
119.5 ± 1.5 ms
Espin0
nuclear quadrupole moment
0
data de descobèrta1965
parity+

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

9He

mass number9
neutron number7
relative atomic mass
9.043946414 ± 0.000050259 Da
g-factor
natural abundance
Radioactivitat☢️ radioactive element
Semivida
2.5 ± 2.3 zs
Espin1/2
nuclear quadrupole moment
0
data de descobèrta1987
parity

decay modeintensity
n (neutron emission)100%

10He

mass number10
neutron number8
relative atomic mass
10.052815306 ± 0.000099676 Da
g-factor
0
natural abundance
Radioactivitat☢️ radioactive element
Semivida
260 ± 40 ys
Espin0
nuclear quadrupole moment
0
data de descobèrta1994
parity+

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

istòria

descobridor o inventaireSir William Ramsey, Nils Langet, P.T.Cleve
luòc de descobèrtaScotland/Sweden
data de descobèrta1895
EtimologiaGreek: hêlios (sun).
pronunciationHEE-li-em (English)

source

Abundance
Abundance in Earth's crust
0.008 mg/kg
natural abundance (Ocean)
0.000007 mg/L
natural abundance (còs uman)
natural abundance (meteoroid)
natural abundance (Solelh)
23 %
Abundance in Universe
23 %

Nuclear Screening Constants

1s0.3125