90  Thorium

 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      

+--------------------+
| 90  _____ _        |
|    |_   _| |__     |
|      | | | '_ \    |
|      | | | | | |   |
|      |_| |_| |_|   |
|                    |
|       Thorium      |
|      232.038 u     |
+--------------------+

Electron Configuration: [Rn]7s2 6d2
Electronegativity:      1.3
Atomic Radius:          237 pm
Ionization Energy:      6.08 eV
Electron Affinity:      
Oxidation States:       4
Standard State:         Solid
Melting Point:          2023 K
Boiling Point:          5061 K
Density:                11.72 g/cm3
Family:                 Actinide
Year Discovered:        1828
Number of Neutrons:     142
Number of Protons:      90
Number of Electrons:    90
Number of Valence:      
Valency:                
Group:                  
Period:                 7
Shell:                  f-shell
Specific Heat:          0.113 J/g K
Radioactive:            1
Occurrence:             Natural
Source:                 Merging neutron stars