History of Atomic Theories Worksheet.doc - Course Hero First modern atomic theory (k) Planck ______ 12. Coined the word "atom" (l) Aristotle ______ 13. Law of definite composition (m) J. J. Thomson ______ 14. Law of conservation of mass (n) Lavoisier ______ 15. Plum pudding model of the atom (o) Gay Lussac ______ 16. Law of multiple proportions (p) Madam Curie ______ 17.