Sub Categories

Nature and Composition of Matter
Atomic Structure
Radioactivity
Isotopes, Isobars, and Isotones
Chemical Bonding
Oxidation and Reduction
Acids, Bases, and Salts
General Properties of Gases
Uptron (likely referring to Plasma or Ionization)
Fuel
Periodic Classification of Elements
Metals and Their Compounds
Non-Metals and Their Compounds
Organic Chemistry