Helium (He)

chemical element with symbol He and atomic number 2; rare gas

Atomic Number	2
Atomic Weight	4.002602
Numri i masës	4

Group	18
Period	1
Block	s

protoni	2 p⁺
neutroni	2 n⁰
elektroni	2 e^-

Tipar Fizik

Atomic Radius	120 pm 134 pm
molar volume	31,8 cm³/mol
covalent radius	46 pm 28 pm
Metallic Radius	122 pm
ionic radius
Crystal Radius
Van der Waals radius	140 pm 140 pm 153 pm 236,2 pm
density	0,000164 g/cm³

Chemical Property

{ERROR}

energjia

proton affinity	177,8 kJ/mol
electron affinity	-19,7 eV/particle
ionization energy	24,587387936 eV/particle 54,41776311 eV/particle

enthalpy of vaporization	0,08 kJ/mol
enthalpy of fusion
standard enthalpy of formation
elektroni

electron shell	2

valence electron	2 ⓘ

konfigurimi i elektronit	1s²ⓘ

oxidation number
Elektronegativiteti	24,59 eV/particle 0.442712
Electrophilicity Index	0,0674191963846371 eV/particle
fundamental state of matter

gjendja agregate e materies
gaseous state of matter	Monoatomic
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
Ngjyra	Black #ffc0cb #d9ffff #d9ffff
appearance	colorless 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 ratio	5/3
electrical properties
type
electrical conductivity
electrical resistivity
Superpërcjellshmëria
Magnetizimi
type	diamagnetic
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
strukturë
Crystal Structure	{ERROR}
lattice constant	3,57 Å
Lattice Angles	π/2, π/2, π/2
mechanical property
hardness
bulk modulus
shear modulus
Young's modulus
Poisson's ratio
Shpejtësia e zërit	970 m/s
klasifikim
Category	Actinides, Noble gases
CAS Group	VIII
IUPAC Group	VIIIA
Glawe Number	1
Mendeleev Number	112
Pettifor Number	1
Geochemical Class	volatile
Goldschmidt classification	atmophile

other

Gas Basicity	148,5 kJ/mol
polarizability	1,38375 ± 0,00002 a₀
C6 Dispersion Coefficient	1,42 a₀ 1,47 a₀
allotrope
Neutron cross section	0,007
Neutron Mass Absorption	0,00001
numër kuantik	1S0
space group	225 (Fm_3m)

Isotopes of Helium

Stable Isotopes	2
Unstable Isotopes	6
Natural Isotopes	2

³He

Numri i masës	3
numri i neutroneve	1
Relative Atomic Mass	3,01602932197 ± 0,00000000006 Da
g-factor	-4,25525062 ± 0,00000006
natural abundance	0,0002 ± 0,0002
Radioaktivitet	stable isotope
half-life	Not Radioactive ☢️
Spini	1/2
nuclear quadrupole moment	0
koha e zbulimit apo shpikjes	1934
parity	+

⁴He

Numri i masës	4
numri i neutroneve	2
Relative Atomic Mass	4,00260325413 ± 0,00000000016 Da
g-factor	0
natural abundance	99,9998 ± 0,0002
Radioaktivitet	stable isotope
half-life	Not Radioactive ☢️
Spini	0
nuclear quadrupole moment	0
koha e zbulimit apo shpikjes	1908
parity	+

⁵He

Numri i masës	5
numri i neutroneve	3
Relative Atomic Mass	5,012057224 ± 0,00002147 Da
g-factor
natural abundance
Radioaktivitet	☢️ radioactive element
half-life	602 ± 22 ys
Spini	3/2
nuclear quadrupole moment
koha e zbulimit apo shpikjes	1937
parity	-

decay mode	intensitet
n (neutron emission)	100%

⁶He

Numri i masës	6
numri i neutroneve	4
Relative Atomic Mass	6,018885889 ± 0,000000057 Da
g-factor	0
natural abundance
Radioaktivitet	☢️ radioactive element
half-life	806,92 ± 0,24 ms
Spini	0
nuclear quadrupole moment	0
koha e zbulimit apo shpikjes	1936
parity	+

decay mode	intensitet
β⁻ (β⁻ decay)	100%
β⁻ d (β⁻-delayed deuteron emission)	0.000278%

⁷He

Numri i masës	7
numri i neutroneve	5
Relative Atomic Mass	7,027990652 ± 0,000008115 Da
g-factor
natural abundance
Radioaktivitet	☢️ radioactive element
half-life	2,51 ± 0,07 zs
Spini	3/2
nuclear quadrupole moment
koha e zbulimit apo shpikjes	1967
parity

decay mode	intensitet
n (neutron emission)	100%

⁸He

Numri i masës	8
numri i neutroneve	6
Relative Atomic Mass	8,033934388 ± 0,000000095 Da
g-factor	0
natural abundance
Radioaktivitet	☢️ radioactive element
half-life	119,5 ± 1,5 ms
Spini	0
nuclear quadrupole moment	0
koha e zbulimit apo shpikjes	1965
parity	+

decay mode	intensitet
β⁻ (β⁻ decay)	100%
β⁻ n (β⁻-delayed neutron emission)	16%
β⁻ t (β⁻-delayed triton emission)	0.9%

⁹He

Numri i masës	9
numri i neutroneve	7
Relative Atomic Mass	9,043946414 ± 0,000050259 Da
g-factor
natural abundance
Radioaktivitet	☢️ radioactive element
half-life	2,5 ± 2,3 zs
Spini	1/2
nuclear quadrupole moment	0
koha e zbulimit apo shpikjes	1987
parity

decay mode	intensitet
n (neutron emission)	100%

¹⁰He

Numri i masës	10
numri i neutroneve	8
Relative Atomic Mass	10,052815306 ± 0,000099676 Da
g-factor	0
natural abundance
Radioaktivitet	☢️ radioactive element
half-life	260 ± 40 ys
Spini	0
nuclear quadrupole moment	0
koha e zbulimit apo shpikjes	1994
parity	+

decay mode	intensitet
2n (2-neutron emission)	100%

historia

zbulues	Sir William Ramsey, Nils Langet, P.T.Cleve
vendndodhja e zbulimit	Scotland/Sweden
koha e zbulimit apo shpikjes	1895
Etimologjia	Greek: hêlios (sun).
pronunciation	HEE-li-em (anglisht)

burim

Abundance
Abundance in Earth's crust	0,008 mg/kg
natural abundance (Oqeani)	0,000007 mg/L
natural abundance (Trupi i njeriut)
natural abundance (meteoroid)
natural abundance (Diell)	23 %
Abundance in Universe	23 %

Nuclear Screening Constants

0.3125

Helium on ChemicalAid

Helium (He)

Tipar Fizik

Chemical Property

other

Isotopes of Helium

3He

4He

5He

6He

7He

8He

9He

10He

historia

burim

Nuclear Screening Constants

³He

⁴He

⁵He

⁶He

⁷He

⁸He

⁹He

¹⁰He