(TXT) Shell: f-block
       
        .                                                  ..
        .. ..                               .  .  .  .  .  ..
        .. ..                               .. .. .  .  .. ..
        .  .. .. .. .  .. .. .. .. .. .. .. .. .. .. .. .. ..
        .. .. .  .. .. .. .. .. .. .. .. .. .. .. .. .. .  ..
        .. .. La .. .. .  .. .. .. .. .. .. .. .. .. .. .. ..
        .. .. Ac .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
                                                             
              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      
       
       The f-block consists of elements in the Lanthanides and Actinides 
       families. The valence electrons of these elements are in the f-shell. 
       This shell holds at most 14 electrons, and has an azimuthal quantum 
       number of 3. The "f" stands for "fundamental".
       
 (DIR)  57 La Lanthanum
 (DIR)  58 Ce Cerium
 (DIR)  59 Pr Praseodymium
 (DIR)  60 Nd Neodymium
 (DIR)  61 Pm Promethium
 (DIR)  62 Sm Samarium
 (DIR)  63 Eu Europium
 (DIR)  64 Gd Gadolinium
 (DIR)  65 Tb Terbium
 (DIR)  66 Dy Dysprosium
 (DIR)  67 Ho Holmium
 (DIR)  68 Er Erbium
 (DIR)  69 Tm Thulium
 (DIR)  70 Yb Ytterbium
 (DIR)  71 Lu Lutetium
 (DIR)  89 Ac Actinium
 (DIR)  90 Th Thorium
 (DIR)  91 Pa Protactinium
 (DIR)  92 U  Uranium
 (DIR)  93 Np Neptunium
 (DIR)  94 Pu Plutonium
 (DIR)  95 Am Americium
 (DIR)  96 Cm Curium
 (DIR)  97 Bk Berkelium
 (DIR)  98 Cf Californium
 (DIR)  99 Es Einsteinium
 (DIR) 100 Fm Fermium
 (DIR) 101 Md Mendelevium
 (DIR) 102 No Nobelium
 (DIR) 103 Lr Lawrencium
       
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