TIGER

21.1 Formations of the Elements
21.2 Terrestrial Elements
21.3 Some Main Group Elements Extracted by Physical Methods: Nitrogen, Oxygen, and Sulfur
21.4 Some Main Group Elements Extracted by Electrolysis: Sodium, Chlorine, Magnesium, And Aluminum
21.5 Some Main Group Elements Extracted by Chemical Oxidation Reduction: Phosphorus, Bromine, and Iodine
21.6 A Periodic Perspective: The Main Group Elements