1803 A.C
John Dalton
Dalton did many experiments with gases as he strived to learn more about them. Dalton's experiments on gases led to his discovery that the total pressure of a mixture of gases amounted to the sum of the partial pressures that each individual gas exerted while occupying the same space.
1780 A.C
Couloumb
Couloumb made advance meets in understanding charges in electrons and how they interact. He created a law, and the law states "The magnitude of the electrostatic force of interaction between two point charges is directly proportional to the scalar multiplication of the magnitudes of charges and inversely proportional to the square of the distance between them."
1700 A.C
Lavoisier
Lavoisier was most well known for his contributions to the understanding of mass in chemical reactions such as measuring weight. He also made strides in understanding combustion.
400 B.c
Democritus
A wise Greek philosopher that is most widely know for his atomic theorem of the universe. This states that everything in the universe is made up of matter and matter consists of atoms.
Chemistry 2nd semester
Evolution of atomic theories through history
1908 A.C
Robert Millikan
Milikan began experiment to measure the charge of a single electron by measuring the course of charged water droplets in an electric field. This was not enough proof so instead he had to replace water and use oil in his experiment.
1905 A.C
Albert Einstein
Albert Einstein had many scientific accomplishment, his contribution to the atomic model was the atomic view of matter. According to the atomic view of matter, a liquid is made up of a huge number of molecules in random, ceaseless motion, the properties of the liquid arising from the average behaviour of its constituent molecules.
1898 A.C
J.J Thompson
Thomas discovered that all matter is made up of particles much smaller than atoms these particles are called electrons. Thomas is also famous for when he discovered that neon was composed of two different kinds of atoms, and proved the existence of isotopes in a stable element.
1898 A.C
The Curies
Pierre and Marie Curie are best known for their pioneering work in the study of radioactivity, which led to their discovery in 1898 of the elements radium and polonium. She was honored with a Nobel prize, but later faced major health problems because of her exposure to radiation.
1932 A.C
James Chadwick
In 1932, Chadwick made a fundamental discovery in the field of nuclear physics: he discovered the particle in the nucleus of the atom that would be called a neutron, a particle that has no electrical charge. In contrast to helium nuclei (alpha particles) that are positively charged and therefore repelled by the electrical forces of the nucleus of heavy atoms, this new tool for atomic disintegration does not need to overcome any electronic barrier and is capable of penetrating and dividing the nucleus of the heavier elements .
1926 A.C
Erwin shrodinger
Schrödinger articulated the movements of electrons in terms of wave mechanics as opposed to particle leaps. This discovery would finalize the evolution of the atomic model as we know it.
1913 A.C
Neils Bohr
Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits.
1909 A.C
Ernest Rutherford
Rutherford postulated the nuclear structure of an atom by "experiments done in Rutherford's laboratory showed that when alpha particles are fired into gas atoms, a few are violently deflected, which implies a dense, positively charged central region containing most of the atomic mass." He did his through the gold foil experiment.
