History Of The Atom Flashcards
What did john dalton say about atoms
Tiny indivisible spheres that each element was made up from (different for each element)
What did J.J. Thomson discover?
J.J. Thomson discovered electrons and created the “plum pudding model” with electrons stuck in a positive sphere.
What experiment disproved the “plum pudding model”?
Rutherford’s gold foil experiment – showed atoms have a dense, positive nucleus with empty space around it.
What did Rutherford discover about the atom?
Rutherford discovered the nucleus – a small, dense, positively charged center surrounded by empty space.
What was Bohr’s improvement to Rutherford’s model?
Bohr proposed that electrons orbit the nucleus in fixed shells or energy levels.
What did experiments after Rutherford show?
Protons were discovered – particles in the nucleus with a positive charge.
Who discovered the neutron?
James Chadwick – he found neutral particles (neutrons) in the nucleus.
What is the modern model of the atom based on?
It combines the nucleus (protons and neutrons) with electrons in shells around it.
What does the gold foil experiment show about atoms?
Most of the atom is empty space, with a small, dense nucleus.
Who disproved the “plum pudding model,” and how?
Ernest Rutherford – gold foil experiment showed atoms have a small, dense nucleus instead of a positive “pudding.”
Who disproved Rutherford’s idea of electrons being in random clouds?
Niels Bohr – showed electrons move in fixed shells instead of random clouds.
