Ilyu (He)

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

Atomic Number	2
Atomic Weight	4.002602
mass number	4

Group	18
Period	1
Block	s

Prutun	2 p⁺
Niwtrun	2 n⁰
Iliktrun	2 e^-

Physical Property

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}

micha

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
Iliktrun

Iñuku hawa	2

valence electron	2 ⓘ

electron configuration	1s²ⓘ

oxidation number
electronegativity	24.59 eV/particle 0.442712
Electrophilicity Index	0.0674191963846371 eV/particle
fundamental state of matter

phase of matter
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
Llimphi	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
superconductivity
Llut'ariy
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
Pawa
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
speed of sound	970 m/s
classification
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
quantum number	1S0
space group	225 (Fm_3m)

Isotopes of Helium

Stable Isotopes	2
Unstable Isotopes	6
Natural Isotopes	2

³He

mass number	3
neutron number	1
Relative Atomic Mass	3.01602932197 ± 0.00000000006 Da
g-factor	-4.25525062 ± 0.00000006
natural abundance	0.0002 ± 0.0002
Illanchaykuy	stable isotope
Kuskan ismuykuy mit'a	Not Radioactive ☢️
spin	1/2
nuclear quadrupole moment	0
time of discovery or invention	1934
parity	+

⁴He

mass number	4
neutron number	2
Relative Atomic Mass	4.00260325413 ± 0.00000000016 Da
g-factor	0
natural abundance	99.9998 ± 0.0002
Illanchaykuy	stable isotope
Kuskan ismuykuy mit'a	Not Radioactive ☢️
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1908
parity	+

⁵He

mass number	5
neutron number	3
Relative Atomic Mass	5.012057224 ± 0.00002147 Da
g-factor
natural abundance
Illanchaykuy	☢️ radioactive element
Kuskan ismuykuy mit'a	602 ± 22 ys
spin	3/2
nuclear quadrupole moment
time of discovery or invention	1937
parity	-

decay mode	intensity
n (neutron emission)	100%

⁶He

mass number	6
neutron number	4
Relative Atomic Mass	6.018885889 ± 0.000000057 Da
g-factor	0
natural abundance
Illanchaykuy	☢️ radioactive element
Kuskan ismuykuy mit'a	806.92 ± 0.24 ms
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1936
parity	+

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

⁷He

mass number	7
neutron number	5
Relative Atomic Mass	7.027990652 ± 0.000008115 Da
g-factor
natural abundance
Illanchaykuy	☢️ radioactive element
Kuskan ismuykuy mit'a	2.51 ± 0.07 zs
spin	3/2
nuclear quadrupole moment
time of discovery or invention	1967
parity

decay mode	intensity
n (neutron emission)	100%

⁸He

mass number	8
neutron number	6
Relative Atomic Mass	8.033934388 ± 0.000000095 Da
g-factor	0
natural abundance
Illanchaykuy	☢️ radioactive element
Kuskan ismuykuy mit'a	119.5 ± 1.5 ms
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1965
parity	+

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

⁹He

mass number	9
neutron number	7
Relative Atomic Mass	9.043946414 ± 0.000050259 Da
g-factor
natural abundance
Illanchaykuy	☢️ radioactive element
Kuskan ismuykuy mit'a	2.5 ± 2.3 zs
spin	1/2
nuclear quadrupole moment	0
time of discovery or invention	1987
parity

decay mode	intensity
n (neutron emission)	100%

¹⁰He

mass number	10
neutron number	8
Relative Atomic Mass	10.052815306 ± 0.000099676 Da
g-factor	0
natural abundance
Illanchaykuy	☢️ radioactive element
Kuskan ismuykuy mit'a	260 ± 40 ys
spin	0
nuclear quadrupole moment	0
time of discovery or invention	1994
parity	+

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

wiñay kawsay

discoverer or inventor	Sir William Ramsey, Nils Langet, P.T.Cleve
location of discovery	Scotland/Sweden
time of discovery or invention	1895
etymology	Greek: hêlios (sun).
pronunciation	HEE-li-em (Ingles Simi)

source

Abundance
Abundance in Earth's crust	0.008 mg/kg
natural abundance (Mama qucha)	0.000007 mg/L
natural abundance (human body)
natural abundance (meteoroid)
natural abundance (Inti)	23 %
Abundance in Universe	23 %

Nuclear Screening Constants

0.3125

Ilyu on ChemicalAid

Ilyu (He)

Physical Property

Chemical Property

other

Isotopes of Helium

3He

4He

5He

6He

7He

8He

9He

10He

wiñay kawsay

source

Nuclear Screening Constants

³He

⁴He

⁵He

⁶He

⁷He

⁸He

⁹He

¹⁰He