| John Dalton | Proposed the first atomic theory of matter (1808) | Dalton’s Atomic Theory |
| Antoine-Laurent de Lavoisier | Identified oxygen; law of conservation of mass; modern chemical nomenclature; metric system | Father of Modern Chemistry |
| Gregor Mendel | Discovered laws of inheritance through pea plant experiments | Father of Genetics |
| Frederick Soddy | Introduced the concept of isotopes | Atomic structure & radioactivity |
| Linus Pauling | Explained chemical bonding using quantum mechanics; electronegativity scale | Pioneer of chemical bonding |
| Gilbert N. Lewis | Electron pair theory of covalent bonding; Lewis dot structures | Lewis Structures |
| Friedrich Kekulé | Proposed the ring structure of benzene | Foundation of Organic Chemistry |