Name: ____________________________ Date: ________________ Period: ________
ICP Chem – Unit 3 – Atomic Theory
Review Sheet
1. Which model of the atom described the atom as an indivisible sphere?
Democritus/John Dalton’s Model
2. Who was the Greek philosopher who came up with the idea of the atom?
Democritus
3. Who was the nineteenth-century scientist who built off this Greek philosopher’s
ideas?
John Dalton
4. List the 3 subatomic particles and tell the charge and where you find them in the
atom.
Subatomic Particle
Charge
Where in the atom?
proton
Positive
In the nucleus
neutron
No charge
In the nucleus
electron
Negative
Surrounding the nucleus in the
electron cloud
5. What is the “plumb pudding” model? (Both explain it and draw a picture).
In the “plumb pudding” model, the atom consists of a blob of positive charge in
which negatively charged electrons are suspended. See the back of p. 28 in
your binder for a picture.
6. Who developed the “plumb pudding” model?
J.J. Thompson
7. How are Rutherford and Bohr’s atoms different from the “plumb pudding” atom?
In Rutherford and Bohr’s models, all the positive charge is concentrated in the
center of the atom instead of spread throughout the atom. The electrons
surround this center.
8. In Bohr’s model of the atom, where are the electrons located?
The electrons orbit the nucleus of the atom.
9. Why is Chlorine-37 heavier than Chlorine-35?
Chlorine-37 has 2 more neutrons than chlorine-35 does.
ICP
Name: ____________________________ Date: ________________ Period: ________
10. Which element has 22 electrons and 24 neutrons? Give the full symbol and full
name.
46
22 Ti, Titanium 46
11. Write the full symbol for zinc-65.
65
30 Zn
12. Write the hyphen notation (full name) for an element with 16 protons and 17
neutrons.
Sulfur-33
27
13. Draw a picture of an atom of 13
Al showing all of the subatomic particles in the
correct region of the atom.
[your picture should include a nucleus of 13 protons and 14 neutrons. There
should be 2 electrons in the first ring around the atom, 8 in the second ring, and 3
in the third ring]
14. What does the atomic number tell us? Where can we find the atomic number?
Atomic number is how many protons are in an element. It is found above the
element symbol on the periodic table.
15. What does the mass number tell us?
Mass # = (# of protons) + (# of neutrons)
16. If you know the mass number and atomic number, how do you find number of
neutrons?
# of neutrons = (mass #) – (# of protons)
17. Which three of the following are the same in an atom? Atomic #, Mass #,
protons, neutrons, electrons
Atomic #, protons, and electrons are all the same
ICP
Name: ____________________________ Date: ________________ Period: ________
18. Which model of the atom showed electrons that were evenly dispersed
throughout the atom?
J.J. Thompson’s “plumb pudding” model
19. Fill in the blanks in the table:
Name
Symbol Protons
Neutrons Electrons Mass Atomic
#
#
Chromium-50
50
24 Cr
24
26
24
50
24
Chlorine-37
37
17 Cl
17
20
17
37
17
Silicon-40
40
14 Si
14
26
14
40
14
Silicon-29
29
14 Si
14
15
14
29
14
Neon-22
22
10 Ne
10
12
10
22
10
20. How big is the electron in comparison to other subatomic particles?
The electron is extremely small.
21. What is an isotope?
An isotope is an atom of the same element, with the same number of protons,
but with a different number of neutrons.
22. What is a nucleus? Where can I find it? Is it dense?
The nucleus is the dense center of an atom. It contains protons and neutrons
23. Identify which scientist was in charge of coming up with each of the following
models for the atom:
A = Rutherford’s atom.
B = Democritus/Dalton’s atom.
C = Thompson’s “plumb pudding” atom.
D = Bohr’s atom.
ICP