This model was developed after J.J. Thompson discovered electrons, a particle smaller than an atom. It shows electrons floating freely in a positive region.
The "Plum Pudding Model" of the atom
Dalton developed the first scientifically tested atomic theory. (T/F)
True
Place the following atomic models in order, from earliest to latest:
C, B, A
Chadwick is credited with discovering which part of the atom?
neutrons
This model this model was the first to show a nucleus, consisting of protons and neutron. Electrons surround the nucleus but are not shown in distinct energy levels.
Rutherford model
What are electrons?
subatomic particles that have negative charges
Who established that "electrons move around the nucleus at fixed distances called orbitals or shells"?
Bohr
What were J. J. Thomson's major contributions to the atomic theory?
Discovered the electron and Proposed the "plum pudding" model of the atom
Which scientist measured the charge on an electron as 1.602 x 10-19 Coulombs?
Millikan
This was the first model of the atom ever proposed. It was simple and described atoms as tiny spheres that could not be broken down into smaller pieces.
Democritus model
Who was the first to propose that matter consist of indivisible particle of matter called atoms?
Democritus
This model added on to previous models by showing electrons existed at certain "energy levels". However it does not accurately show what those levels look like.
The "Bohr Model" of the atom
This is the most complete and current model of the atom. It consists of 61 elementary particles. Electrons are located in complex orbitals.
Schrödinger model
What subatomic particles make up the nucleus of an atom?
Protons and neutrons
Ernest Rutherford discovered that atoms were mostly _________________.
Empty space
The cathode-ray tube was used to discover the ____ by ____.
electron by Thomson
Which scientist proposed the "plum pudding model" of the atom?
J. J. Thomson
Which scientist is responsible for first stating that all the atoms of a particular element are identical but are different from the atoms of all other elements?
Dalton
What scientist is best known for his gold foil experiment?
Ernest Rutherford
What is the meaning of the greek word "atomos"?
Indivisible or uncuttable
In the gold foil experiment, most of the positively charged alpha particles passed through the gold foil, but some were deflected or bounced back. What did we conclude because of this?
Atoms are mostly empty space with a small, dense, positive center
In the atomic model nicknamed the "plum pudding" model, what do the plums represent?
Electrons
In Rutherford's famous "Gold Foil" experiment, some particles passed through the foil, some were deflected, and some were bounced straight back. This observation made Rutherford conclude
gold atoms have a solid nucleus
Aristotle and other early Greek philosophers thought that matter was composed of four elements: air, earth, fire, and water(T/F)
True
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