Discovered By: Lord Rayleigh, Sir William Ramsay
Discovery year: 1894

The following table showing some properties of Argon(Ar):

Table Example
Atomic number 18
Group 18
Period 3
Block p
Electrons 18
Protons 18
Neutrons 22
Atomic weight 39.948
Oxidation states 0
Electrons per shell K2 L8 M8


Table Example
Electron conigurtion 1s^2 2s^2 2p^6 3s^2 3p^6
Gas atomic multiplicities 1
Atomic radius 71 pm
Covalent radius 106 pm
Van der Waals radius 188 pm
Boiling point -185.8°C
Melting point -189.3°C
Phase Gas
Fusion heat 1.18 kJ.mol^-1
Vaporization heat 6.5 kJ.mol^-1


Table Example
Color Colorless
Density 1.784 kg.m^-3
Molar volume 2.239*10^-2 m^3.mol^-1
Refractive index 1.000281
Sound speed 319 m.s^-1
Thermal coductivity 0.01772 W.m^-1.K^-1
Magnetic type Diamagnetic
Volume magnetic susceptibility -1.07*10^-8
Mass magnetic susceptibility -6*10^-9 m^3.kg^-1
Molar magnetic susceptibility -2.4*10^-10 m^3.mol^-1


Table Example
Valence 0
Electron affinity 0 kJ.mol^-1
First ionization energy 1520.6 kJ.mol^-1
Radioactive No
Neutron cross section 0.65 barn
Specific heat 520.33 J.kg^-1.K^-1