Atomic Number | 18 |
---|---|
Atomic Weight | 39.948 |
Mass Number | 40 |
Group | 18 |
---|---|
Period | 3 |
Block | p |
Protons | 18 p+ |
---|---|
Neutrons | 22 n0 |
Electrons | 18 e- |
Atomic Radius | 71 pm
|
---|---|
Molar Volume | 24.2 cm³/mol
|
Covalent Radius | 96 pm
|
Metallic Radius | |
Ionic Radius | |
Crystal Radius | |
Van der Waals Radius |
188 pm
|
Density | 0.001633 g/cm³
|
Energy | |
Proton Affinity | 369.2 kJ/mol
|
Electron Affinity | -11.5 eV/particle
|
Ionization Energy | 15.7596112 eV/particle
|
Heat of Vaporization | 6.52 kJ/mol
|
Heat of Fusion | |
Heat of Formation | |
Electrons | |
Electron Shells | 2, 8, 8 |
Valence Electrons | 0 |
Electron Configuration | [Ne] 3s2 3p6 |
Oxidation States | 0 |
Electronegativity | |
Electrophilicity | 0.0832013314590371 eV/particle
|
Phases | |
Phase | Gas |
Gas Phase | Monoatomic |
Boiling Point | 87.302 K
|
Melting Point | 83.81 K
|
Critical Pressure | 4.863 MPa
|
Critical Temperature | 150.687 K
|
Triple Point | |
Visual | |
Color | Colorless
|
Appearance | colorless gas exhibiting a lilac/violet glow when placed in a high voltage electric field |
Refractive Index | 1.000281
|
Thermodynamic Properties | |
Thermal Conductivity | 0.0177 W/(m K)
|
Thermal Expansion | |
Molar Heat Capacity | 20.786 J/(mol K)
|
Specific Heat Capacity | 0.52 J/(g⋅K)
|
Heat Capacity Ratio (Adiabatic Index) | 5/3 |
Electrical Properties | |
Type | |
Electrical Conductivity | |
Electrical Resistivity | |
Superconducting Point | |
Magnetism | |
Type | diamagnetic |
Magnetic Susceptibility (Mass) | -0.000000006 m³/Kg
|
Magnetic Susceptibility (Molar) | -0.00000000024 m³/mol
|
Magnetic Susceptibility (Volume) | -0.0000000107
|
Magnetic Ordering | |
Curie Point | |
Neel Point | |
Structure | |
Crystal Structure | Face Centered Cubic (FCC) |
Lattice Constant | 5.26 Å
|
Lattice Angles | π/2, π/2, π/2 |
Mechanical Properties | |
Hardness | |
Bulk Modulus | |
Shear Modulus | |
Young Modulus | |
Poisson Ratio | |
Speed of Sound | 319 m/s
|
Classification | |
Category | Noble gases, Noble gases |
CAS Group | VIII |
IUPAC Group | VIIIA |
Glawe Number | 3 |
Mendeleev Number | 114 |
Pettifor Number | 3 |
Geochemical Class | volatile |
Goldschmidt Class | atmophile |
Other | |
Gas Basicity | 346.3 kJ/mol
|
Dipole Polarizability | |
C6 Dispersion Coefficient | 64.2 a₀
|
Allotropes | |
Neutron Cross Section | 0.66
|
Neutron Mass Absorption | 0.00059
|
Quantum Numbers | 1S0 |
Space Group | 225 (Fm_3m) |
Stable Isotopes | 3 |
---|---|
Unstable Isotopes | 23 |
Radioactive Isotopes | 22 |
Abundance | |
---|---|
Relative Atomic Mass | |
Mass Number | 29 |
G-Factor | |
Half Life | |
Spin | 5/2 |
Quadrupole Moment | |
Discovery Year | 2018 |
Parity | + |
Decay Mode | Intensity |
---|---|
2p (2-proton emission) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 30 |
G-Factor | 0
|
Half Life | |
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 2015 |
Parity | + |
Decay Mode | Intensity |
---|---|
2p (2-proton emission) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 31 |
G-Factor | |
Half Life | 15 ± 0.3 ms
|
Spin | 5/2 |
Quadrupole Moment | |
Discovery Year | 1986 |
Parity | + |
Decay Mode | Intensity |
---|---|
β+ (β+ decay; β+ = ϵ + e+) | 100% |
β+ p (β+-delayed proton emission) | 68.3% |
2p (2-proton emission) | 9% |
B+pA | 0.38% |
3p | 0.07% |
β+α (β+-delayed α emission) | 0.03% |
2p (2-proton emission) | 0.0006% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 32 |
G-Factor | 0
|
Half Life | 98 ± 2 ms
|
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1977 |
Parity | + |
Decay Mode | Intensity |
---|---|
β+ (β+ decay; β+ = ϵ + e+) | 100% |
β+ p (β+-delayed proton emission) | 35.58% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 33 |
G-Factor | -1.446 ± 0.012
|
Half Life | 173 ± 2 ms
|
Spin | 1/2 |
Quadrupole Moment | 0
|
Discovery Year | 1964 |
Parity | + |
Decay Mode | Intensity |
---|---|
β+ (β+ decay; β+ = ϵ + e+) | 100% |
β+ p (β+-delayed proton emission) | 38.7% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 34 |
G-Factor | 0
|
Half Life | 846.46 ± 0.35 ms
|
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1966 |
Parity | + |
Decay Mode | Intensity |
---|---|
β+ (β+ decay; β+ = ϵ + e+) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 35 |
G-Factor | 0.42133333333333 ± 0.00013333333333333
|
Half Life | 1.7756 ± 0.001 s
|
Spin | 3/2 |
Quadrupole Moment | -0.084 ± 0.015
|
Discovery Year | 1940 |
Parity | + |
Decay Mode | Intensity |
---|---|
β+ (β+ decay; β+ = ϵ + e+) | 100% |
Abundance | 0.3336 ± 0.021
|
---|---|
Relative Atomic Mass | |
Mass Number | 36 |
G-Factor | 0
|
Half Life | |
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1920 |
Parity | + |
Decay Mode | Intensity |
---|---|
2β+ (double β+ decay) | % |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 37 |
G-Factor | |
Half Life | 35.011 ± 0.019 d
|
Spin | 3/2 |
Quadrupole Moment | 0.076 ± 0.003
|
Discovery Year | 1941 |
Parity | + |
Decay Mode | Intensity |
---|---|
ϵ (electron capture) | 100% |
Abundance | 0.0629 ± 0.007
|
---|---|
Relative Atomic Mass | |
Mass Number | 38 |
G-Factor | 0
|
Half Life | |
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1934 |
Parity | + |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 39 |
G-Factor | -0.45428571428571 ± 0.0042857142857143
|
Half Life | 268 ± 8 y
|
Spin | 7/2 |
Quadrupole Moment | -0.116 ± 0.002
|
Discovery Year | 1950 |
Parity | - |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
Abundance | 99.6035 ± 0.025
|
---|---|
Relative Atomic Mass | |
Mass Number | 40 |
G-Factor | 0
|
Half Life | |
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1920 |
Parity | + |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 41 |
G-Factor | -0.37428571428571 ± 0.0022857142857143
|
Half Life | 109.61 ± 0.04 m
|
Spin | 7/2 |
Quadrupole Moment | -0.042 ± 0.004
|
Discovery Year | 1936 |
Parity | - |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 42 |
G-Factor | 0
|
Half Life | 32.9 ± 1.1 y
|
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1952 |
Parity | + |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 43 |
G-Factor | -0.4088 ± 0.0024
|
Half Life | 5.37 ± 0.06 m
|
Spin | 5/2 |
Quadrupole Moment | 0.142 ± 0.014
|
Discovery Year | 1969 |
Parity |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 44 |
G-Factor | 0
|
Half Life | 11.87 ± 0.05 m
|
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1969 |
Parity | + |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 45 |
G-Factor | |
Half Life | 21.48 ± 0.15 s
|
Spin | 5/2 |
Quadrupole Moment | |
Discovery Year | 1974 |
Parity | - |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 46 |
G-Factor | 0
|
Half Life | 8.4 ± 0.6 s
|
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1974 |
Parity | + |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 47 |
G-Factor | |
Half Life | 1.23 ± 0.03 s
|
Spin | 3/2 |
Quadrupole Moment | |
Discovery Year | 1985 |
Parity |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
β− n (β−-delayed neutron emission) | 0.2% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 48 |
G-Factor | 0
|
Half Life | 415 ± 15 ms
|
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 2004 |
Parity | + |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
β− n (β−-delayed neutron emission) | 38% |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 49 |
G-Factor | |
Half Life | 236 ± 8 ms
|
Spin | 3/2 |
Quadrupole Moment | |
Discovery Year | 1989 |
Parity | - |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
β− n (β−-delayed neutron emission) | 29% |
2n (2-neutron emission) | % |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 50 |
G-Factor | 0
|
Half Life | 106 ± 6 ms
|
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 1989 |
Parity | + |
Decay Mode | Intensity |
---|---|
β− (β− decay) | 100% |
β− n (β−-delayed neutron emission) | 37% |
2n (2-neutron emission) | % |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 51 |
G-Factor | |
Half Life | |
Spin | 1/2 |
Quadrupole Moment | 0
|
Discovery Year | 1989 |
Parity | - |
Decay Mode | Intensity |
---|---|
β− (β− decay) | % |
β− n (β−-delayed neutron emission) | % |
2n (2-neutron emission) | % |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 52 |
G-Factor | 0
|
Half Life | |
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 2009 |
Parity | + |
Decay Mode | Intensity |
---|---|
β− (β− decay) | % |
β− n (β−-delayed neutron emission) | % |
2n (2-neutron emission) | % |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 53 |
G-Factor | |
Half Life | |
Spin | 5/2 |
Quadrupole Moment | |
Discovery Year | 2009 |
Parity | - |
Decay Mode | Intensity |
---|---|
β− (β− decay) | % |
β− n (β−-delayed neutron emission) | % |
2n (2-neutron emission) | % |
Abundance | Radioactive ☢️ |
---|---|
Relative Atomic Mass | |
Mass Number | 54 |
G-Factor | 0
|
Half Life | |
Spin | 0 |
Quadrupole Moment | 0
|
Discovery Year | 2018 |
Parity | + |
Decay Mode | Intensity |
---|---|
β− (β− decay) | % |
β− n (β−-delayed neutron emission) | % |
2n (2-neutron emission) | % |
Argon was suspected to be present in air by Henry Cavendish in 1785. It was not isolated until 1894 by Lord Rayleigh and Sir William Ramsay in Scotland. Argon became the first member of the noble gases to be discovered. In 1957, IUPAC agreed that the symbol should change from A to Ar. From the Greek argos, inactive
Discoverers | Sir William Ramsey, Baron Rayleigh |
---|---|
Discovery Location | Scotland |
Discovery Year | 1894 |
Etymology (Name Origin) | Greek: argos (inactive). |
Pronunciation | AR-gon (English) |
Continuously released into the air by decay of radioactive potassium-40. Pure form is obtained from fractional distillation of liquid air.
Abundance | |
---|---|
Abundance in Earth's crust | 3.5 mg/kg
|
Abundance in Oceans | 0.45 mg/L
|
Abundance in Human Body | |
Abundance in Meteor | |
Abundance in Sun | 0.007 %
|
Abundance in Universe | 0.02 %
|
1 | s | 0.4925 |
2 | p | 3.9918 |
2 | s | 5.7696 |
3 | p | 11.2359 |
3 | s | 10.2432 |