The development of atomic theory has been marked by significant discoveries from various scientists throughout history. Henri Becquerel's discovery of radioactivity in 1896 laid the foundation for understanding atomic behavior, and in 1897, J.
He was the one who discovered the neutron. The neutron aids in the balance of protons in an atom's nucleus.
Chadwick
1925
He thought of the Uncertainty Principle. According to the principle, one can never know the exact position and energy of an electron at the same time.
Heisenberg
1913
Fredrick Soddy
He invented the notion of isotopes. Explain to Ernest Rutherford that radiation is caused by elemental transmutation.
Neils Bohr
He explained that an atom's outer orbits might hold more electrons than its inner orbits. Knowing this allows one to calculate the chemical characteristics of an atom. He also proposed that electrons emit light by hopping orbits.
1910
He determined the charge of a single electron using an oil drop experiment.
Millikan
1907
He discovered the present model of an atom using the gold foil experiment. He came to the conclusion that all positive charge was centred, and negative electrons orbited the nucleus.
Ernest Rutherfor
1897
He was the one who discovered the electron. He tested and studied the nature of electric discharge in a high vacuum cathode-ray tube.
J.J. Thomson
1896
He was awarded the Nobel Prize for discovering radioactivity. It was also discovered that uranium rays caused gases to ionize.
Henri Becquerel
1885
Positive particles were discovered. Taking into consideration that the particles had a charge of equal and opposite to the electron
Eugene Goldstein
1869
He developed the periodic table of elements, which arranges elements based on similarities. His Period Law asserts that "physical and chemical properties of elements are periodic functions of their atomic numbers."
Mendeleev
1803
Dalton agreed that atoms, which he believed were indestructible, generated all matter. Also, compounds are formed by combining two atoms, and all atoms of a specific element have equal mass attributes (Dalton's atom Theory).
Dalton
460 BC
All matter, including space and time, was proposed to be made up of microscopic units known as atoms. Despite the fact that he conducted no experiments and had no proof, Lucretius retained his idea.
Democritus
492 BC
He believed that all matter was made up of four elements: fire, air, water, and earth.