Academic Chemistry
Name: _____________________________
Chapter 4 Study Guide
Date Due: __________________________
115 Points
`
Block/Day: __________________________
Complete the following sentences. Incomplete answers will be marked incorrect. Be specific
with your answers. Be sure to include units on all numerical answers. One point for each
blank or set of blanks, unless otherwise noted.
1. A _____________ is the smallest particle of an element that retains the properties in a
___________________ ______________________. (2 points)
2. Democritus believed that atoms where __________________________ and
______________________. (2 points)
3. What did Democritus lack when putting forth his ideas? (2 points)
______________________________________________________________
4. Who came up with the first accepted atomic theory? ____________________________
5. What did his theory have that Democritus ‘ theory lacked? (2 points)
________________________________________________________________
6. List the 4 points of Dalton’ s Atomic Theory (8 points):

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________
7. What is the range of sizes of the radii of most atoms? (6 points)
_________________________________________________________
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8. What instrument allows us to observe atoms? __________________________________
9. Name the 3 subatomic particles ___________________, ____________________, and
_______________________. (3 points)
10. Who found the first subatomic particle and what particle did he find? __________________
_____________________. (2 points)
11. He used the ________________ ___________ ____________ to find the particle.
12. The glowing beam is called the __________________ ________________.
13. He determined what ratio for these particles? ___________________________________
14. How did he determine that this particle was found in all atoms? (4 points)
____________________________________________________________________________________
__________________________________________________________________.
15. Robert Millikan determined _________________________________________________. (2
points)
16. Complete the following chart? (15 points)
Particle
Symbol
Charge
Relative Mass
Actual Mass
Electron
1+
n0
17. __________________ __________________ discovered the proton by discovering
__________________ _______________ in cathode ray tubes. (2 points)
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18. _________________ ___________________ confirmed the existence of another subatomic
particle with no charge and a mass similar to the proton, called the
_____________________________. (2 points)
19. _____________________ _______________________ discovered the nucleus in his famous
_______________ _______________ experiment. (2 points)
20. He probed the atom with a(n) _____________ _____________.
21. He concluded the following (5 points);

__________________________________________________________________

__________________________________________________________________
22. His atomic model is known as the ____________________ ____________________.
23. Describe his atomic model. (2 points) _______________________________________
________________________________________________________________________
24. Elements are different because they contain different numbers of
_______________________.
25. The number of protons in an atom is given by its _____________ ________________.
26. Because the atom is electrically neutral, the number of ___________________ equals the
number of _______________________. (2 points)
27. The mass number is determined by the sum of the ___________________ and the
________________________. (2 points)
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28. Complete the following table: (18 points)
Element
Mass
Atomic
Number
Number
K
Protons
Neutrons
Electrons
39
11
5
16
23
29. The isotope of carbon with a mass number of 14 can be written either as _____________ or
_______________________________. (2 points)
30. A(n) ___________________ has different numbers of neutrons and different mass numbers.
31. The mass of an atom is measured in ___________________ ________________
__________________.
32. This unit above is defined as _______________ the mass of ___________________________.
(2 points)
33. The ________________ ________________ is the weighted average of the naturally
occurring isotopes of the element.
34. What is the formula for determining the average atomic mass? (2 points)
35. The abundance must be expressed as a _______________________ in this formula.
36. The arrangement of elements based on repeating properties is called the
________________________ ______________________.
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37. A horizontal row is called a __________________________ and there are
___________________ of these in our current table. (2 points)
38. A vertical column is called a _______________________ and there are
______________________ of these in our current table. (2 points)
39. Four isotopes of lead are listed in the table below. Calculate the approximate atomic mass
of lead based on this information. (8 points – 2 points work, 2 points number, 2 points
significant figures, 2 points units)
Protons
Neutrons
Percent Abundance
82
122
1.4%
82
124
24.1%
82
125
22.1%
82
126
52.4%
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