(TXT) Shell: s-block
       
        H                                                  He
        Li Be                               .  .  .  .  .  ..
        Na Mg                               .. .. .  .  .. ..
        K  Ca .. .. .  .. .. .. .. .. .. .. .. .. .. .. .. ..
        Rb Sr .  .. .. .. .. .. .. .. .. .. .. .. .. .. .  ..
        Cs Ba .. .. .. .  .. .. .. .. .. .. .. .. .. .. .. ..
        Fr Ra .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
                                                             
              .. .. .. .. .. .. .. .. .. .. .. .. .. ..      
              .. .. .  .. .. .. .. .. .. .. .. .. .. ..      
       
       The s-block consists of elements in Groups 1 and 2 plus Helium. The 
       valence electrons of these elements are in the s-shell. This 
       spherical shaped shell holds at most 2 electrons, and has an 
       azimuthal quantum number of 0. The "s" stands for "sharp".
       
 (DIR)   1 H  Hydrogen
 (DIR)   2 He Helium
 (DIR)   3 Li Lithium
 (DIR)   4 Be Beryllium
 (DIR)  11 Na Sodium
 (DIR)  12 Mg Magnesium
 (DIR)  19 K  Potassium
 (DIR)  20 Ca Calcium
 (DIR)  37 Rb Rubidium
 (DIR)  38 Sr Strontium
 (DIR)  55 Cs Cesium
 (DIR)  56 Ba Barium
 (DIR)  87 Fr Francium
 (DIR)  88 Ra Radium
       
 (DIR) All Shells