Atomic Theorys Flashcards
All matter can be divided into smaller pieces until a single invisible particle is reached
He named the single invisible particle the “atom”
He proposed all atoms are of different sizes, in constant motion, and separate by empty space
Democritus
All matters made by tiny, invisible particles called atoms
Rearranged to form substances and chemical reactions, but they’re never created or destroyed
John dalton
Use the cathode tube experiment discover the extremely negatively charged particles called the electron
He said Adam are spheres, made up of solid positive mass with tiny negative particles embedded in it
J.J. Thompson
he completed the gold foil experiment and discovered that the nucleus surrounded by negatively charged cloud of electrons and most of the atoms empty space
He also discovered the nucleus of the atom has a positive proton contains most of the atom mass, but occupies a very small space
Ernest Rutherford
Use the atom spectrum of hydrogen electrons placed in definite orbitals from the nucleus
Electrons cannot be between orbits and first orbit can hold electrons next to can hold 8
Niels Bohr
He discovered the neutral particles (neutrons) and that the mass of the neutron the same as a proton
James Chadwick
Electrons do not travel in an exact orbit, but rather in clouds
Modern theory
