First proposed the existence of an ultimate particle. It was nicknamed "atomos".
Believed all substances were made of fire, water, air, and earth. He also believed that if you cut matter in half, you would always have a smaller piece.
Discovered the Law of Conservation of Matter. Matter is neither created nor destroyed in a chemical reaction.
Proposed the Law of Constant Composition.
Discovered the Law of Multiple Proportions and reintroduced the atomic theory to explain chemical reactions.
Discovered Thallium and Cathode Rays
provided the first theoretical explanation for the splitting of the atom, and coined a new term in physics: fission.
Discovered Mesothorium, Protactinium, and Uranium
Discovered this subatomic particle by using a neutron chamber in his experiments.
Discovered radioactivity while experimenting with uranium and a photographic plate.
Discovered negatively charged electron. Measured electrons charge-to-mass ratio and identified electrons as fundamental particles.
Proposed the quantum theory. E = H x frequency
He proposed that light was made up of quantized photons.
Discovered charge on electron. Studied charged oil droplets in an electric field.
Developed the Gold Foil Experiment
Proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined qualities.
Formulated quantum mechanics
Postulated matter waves. Matter waves in atoms are standing waves.
Included quantum mechanics to the atomic theory
he published many important contributions to the then newly developed quantum theory, most notably a famous paper on the so-called Born-Oppenheimer approximation, which separates nuclear motion from electronic motion in the mathematical treatment of molecules.
invented the cyclotron, a device for accelerating nuclear particles to very high velocities without the use of high voltages.
Evolved the beta-decay theory.
Discovered how to synthesize designer radioactive elements
Discovered Plutonium and all further transuranium elements through element 102