Helium

Helium (He)

chemical element with symbol He and atomic number 2; rare gas
Atomic Number2
Atomic Weight4.002602
Nombor jisim4
Group18
Period1
Blocks
proton2 p+
neutron2 n0
Elektron2 e-
Animated Model Bohr of He (Helium)

Sifat Fizikal

Jejari Atom
120 pm
molar volume
Jejari kovalen
46 pm
Metallic Radius
ionic radius
Crystal Radius
Jejari van der Waals
140 pm
ketumpatan
0.000164 g/cm³
Atomic Radii Of The Elements: Helium0102030405060708090100110120130140pmJejari AtomJejari KovalenMetallic RadiusJejari van der Waals

Sifat Kimia

tenaga
proton affinity
177.8 kJ/mol
Pertalian elektron
ionization energy
24.587387936 eV/particle
ionization energy of He (Helium)
Entalpi pengewapan
0.08 kJ/mol
entalpi pelakuran
standard enthalpy of formation
Elektron
Petala elektron2
Model Bohr: He (Helium)
Elektron valens2
Teori ion Lewis: He (Helium)
tatarajah elektron1s2
Enhanced Model Bohr of He (Helium)
Orbital Diagram of He (Helium)
Keadaan pengoksidaan
Keelektronegatifan
Electrophilicity Index
0.0674191963846371 eV/particle
keadaan jirim asas
fasa jirimGas
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
rupa
warna
Colorless
rupacolorless gas, exhibiting a red-orange glow when placed in a high-voltage electric field
indeks biasan
1.000035
sifat bahan
Thermal Conductivity
0.152 W/(m K)
Pengembangan terma
molar heat capacity
20.786 J/(mol K)
Specific Heat Capacity
5.193 J/(g⋅K)
heat capacity ratio5/3
electrical properties
type
Kekonduksian elektrik
Kerintangan dan kekonduksian elektrik
Kesuperkonduksian
kemagnetan
typediamagnetic
magnetic susceptibility (Mass)
-0.0000000059 m³/Kg
magnetic susceptibility (Molar)
-0.0000000000236 m³/mol
magnetic susceptibility (Volume)
-0.00000000105
magnetic ordering
Suhu Curie
Néel temperature
struktur
Crystal StructureFace Centered Cubic (HEX)
lattice constant
3.57 Å
Lattice Anglesπ/2, π/2, π/2
mechanical property
hardness
Modulus pukal
shear modulus
Young's modulus
Nisbah Poisson
Kelajuan bunyi
970 m/s
pengelasan
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
Nombor kuantum1S0
space group225 (Fm_3m)

Isotopes of Helium

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

3He

Nombor jisim3
nombor neutron1
jisim atom relatif
3.01602932197 ± 0.00000000006 Da
g-factor
-4.25525062 ± 0.00000006
natural abundance
0.0002 ± 0.0002
Reputan radioaktifIsotop stabil
setengah hayatNot Radioactive ☢️
Spin1/2
nuclear quadrupole moment
0
tarikh penemuan1934
parity+

4He

Nombor jisim4
nombor neutron2
jisim atom relatif
4.00260325413 ± 0.00000000016 Da
g-factor
0
natural abundance
99.9998 ± 0.0002
Reputan radioaktifIsotop stabil
setengah hayatNot Radioactive ☢️
Spin0
nuclear quadrupole moment
0
tarikh penemuan1908
parity+

5He

Nombor jisim5
nombor neutron3
jisim atom relatif
5.012057224 ± 0.00002147 Da
g-factor
natural abundance
Reputan radioaktif☢️ radioactive element
setengah hayat
602 ± 22 ys
Spin3/2
nuclear quadrupole moment
tarikh penemuan1937
parity-

decay modeKeamatan (fizik)
n (neutron emission)100%

6He

Nombor jisim6
nombor neutron4
jisim atom relatif
6.018885889 ± 0.000000057 Da
g-factor
0
natural abundance
Reputan radioaktif☢️ radioactive element
setengah hayat
806.92 ± 0.24 ms
Spin0
nuclear quadrupole moment
0
tarikh penemuan1936
parity+

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

7He

Nombor jisim7
nombor neutron5
jisim atom relatif
7.027990652 ± 0.000008115 Da
g-factor
natural abundance
Reputan radioaktif☢️ radioactive element
setengah hayat
2.51 ± 0.07 zs
Spin3/2
nuclear quadrupole moment
tarikh penemuan1967
parity

decay modeKeamatan (fizik)
n (neutron emission)100%

8He

Nombor jisim8
nombor neutron6
jisim atom relatif
8.033934388 ± 0.000000095 Da
g-factor
0
natural abundance
Reputan radioaktif☢️ radioactive element
setengah hayat
119.5 ± 1.5 ms
Spin0
nuclear quadrupole moment
0
tarikh penemuan1965
parity+

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

9He

Nombor jisim9
nombor neutron7
jisim atom relatif
9.043946414 ± 0.000050259 Da
g-factor
natural abundance
Reputan radioaktif☢️ radioactive element
setengah hayat
2.5 ± 2.3 zs
Spin1/2
nuclear quadrupole moment
0
tarikh penemuan1987
parity

decay modeKeamatan (fizik)
n (neutron emission)100%

10He

Nombor jisim10
nombor neutron8
jisim atom relatif
10.052815306 ± 0.000099676 Da
g-factor
0
natural abundance
Reputan radioaktif☢️ radioactive element
setengah hayat
260 ± 40 ys
Spin0
nuclear quadrupole moment
0
tarikh penemuan1994
parity+

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

sejarah

penemu atau perekaSir William Ramsey, Nils Langet, P.T.Cleve
tempat penemuanScotland/Sweden
tarikh penemuan1895
EtimologiGreek: hêlios (sun).
sebutanHEE-li-em (Inggeris)

sumber

Abundance
Abundance in Earth's crust
0.008 mg/kg
natural abundance (lautan)
0.000007 mg/L
natural abundance (Tubuh manusia)
natural abundance (Meteoroid)
natural abundance (Matahari)
23 %
Abundance in Universe
23 %

Nuclear Screening Constants

1s0.3125