18  Argon

 H                                                  He
 Li Be                               B  C  N  O  F  Ne
 Na Mg                               Al Si P  S  Cl[Ar]
 K  Ca Sc Ti V  Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
 Rb Sr Y  Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I  Xe
 Cs Ba La Hf Ta W  Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
 Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
                                                      
       Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu      
       Th Pa U  Np Pu Am Cm Bk Cf Es Fm Md No Lr      

+--------------------+
| 18    _            |
|      / \   _ __    |
|     / _ \ | '__|   |
|    / ___ \| |      |
|   /_/   \_\_|      |
|                    |
|        Argon       |
|       39.9 u       |
+--------------------+

Electron Configuration: [Ne]3s2 3p6
Electronegativity:      
Atomic Radius:          188 pm
Ionization Energy:      15.760 eV
Electron Affinity:      
Oxidation States:       0
Standard State:         Gas
Melting Point:          83.8 K
Boiling Point:          87.3 K
Density:                0.0017837 g/cm3
Family:                 Noble gas
Year Discovered:        1894
Number of Neutrons:     22
Number of Protons:      18
Number of Electrons:    18
Number of Valence:      8
Valency:                0
Group:                  18
Period:                 3
Shell:                  p-shell
Specific Heat:          0.520 J/g K
Radioactive:            0
Occurrence:             Natural
Source:                 Dying high-mass stars
Source:                 White dwarf supernovae