Name: ____________________
Timeline of Atomic Models
A Flipped Lesson
Instructions: Watch the video entitled “Timeline of Atomic Models”
posted on the class website and answer the questions below. This
assignment MUST be completed before Thursday 9/24.
1. Democritus’s Early Ideas about Atoms (2500 years ago):
a) ___________________ and Leucippus developed the idea of “atomos”.
b) What does “atomos” mean?
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c) What is one downfall of Democritus’ idea about atoms? (2:20)
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2. John Dalton’s Cannonball/Billiard Ball Model of the Atom (1808):
a) Matter consists of ___________________ atoms. (This means that they
cannot be broken down into any smaller parts.) (3:00)
b) Atoms arrange in different combinations to make different
____________________. (3:05)
3. J.J. Thomson’s Plum Pudding Model (1904):
a) What is one main difference between J.J. Thomson’s Plum Pudding Model
and John Dalton’s Cannonball Model? (3:50; 5:07)
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b) Draw a labeled diagram of J.J. Thomson’s Plum Pudding Model.
c) Why is the atom “electrically neutral”? (4:45)
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4. Ernest Rutherford’s Nuclear Model of the Atom (1911):
a) What was the name of Ernest Rutherford’s experiment?
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b) Draw a labeled diagram of Ernest Rutherford’s Nuclear Model.
c) What two things did Ernest Rutherford discover while conducting his
experiment?
i) (5:23; 5:44)
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ii) (5:32)
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5. Niels Bohr’s Planetary Model of the Atom (1913)
a) What is one similarity between Niels Bohr’s model of the atom and
Rutherford’s model of the atom?
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b) (6:23) In terms of electrons, how is Niel’s Bohr’s model of the atom
different than Rutherford’s model?
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c) Draw a labeled diagram of Niels Bohr’s Model of the atom.
6. Erwin Schrödinger’s Quantum Mechanical (Electron Cloud)
Model of the Atom
(1920s)
a) In terms of electron location, what is one difference between Niels Bohr’s
Model of the atom versus Schrödinger’s model of the atom?
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b) Draw a labeled diagram of the Quantum Mechanical Model of the atom,
including the protons and neutrons (8:55).
c) What is the difference between an “orbit” and an “orbital”?
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Subatomic
Particle
Proton
Electron
Neutron
Summarize:
Discovered By
Location in
Atom
Charge
**Why do we often use Bohr’s model (orbits) instead of Schrodinger’s
model (orbitals)? **
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