Atomic Theories Flashcards
Who theorized that all matter can be divided into smaller pieces until a single invisible particle is reached
Democritus (400BC)
Who named a single invisible particle the “Atom”
Democritus (400BC)
Theorized all atoms are different sizes, in constant motion, and not touching
Democritus (400BC)
John Daltons model?
“Billard ball”
Theorized All matter is made up of tiny invisible particles called atoms
Atoms are rearranged to form a new substance in chemical reactions, but they are never created or destroyed
John Dalton (1803)
Used the cathode ray tube experiment to discover extremely small negatively charged particles, called the electron
J.J. Thompson (1904)
Theorized atoms are solid spheres made up of a solid positive mass with tiny negative particles embedded in it
J.J. Thompson (1904)
J.J. Thompson (1904) model
Chocolate Chip cookie / plum pudding model
Who completed the gold foil experiment?
Ernest Rutherford
Theorized the nucleus has a positive charge proton contains most of an atoms mass but occupies a small space
Ernest Rutherford
Niels Bohr’s model?
Planetary model
Who used the atomic spectrum of hydrogen to prove that electrons are placed in definite orbitals around the nucleus
Niels Bohr (1913)
What did Niels Bohr theorize
Electrons cannot be between orbits the first orbit can contain 2 electrons the rest can contain 8 electrons
Theorized mass of n° = p+
James Chadwick (1932)
Theorized electrons don’t travel in exact orbit but in clouds
Modern theory
