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Name ___________________________
4.1
Date ___________________
Class __________________
DEFINING THE ATOM
Section Review
Objectives
• Describe Democritus’s ideas about atoms
• Explain Dalton’s atomic theory
• Describe the size of an atom
Vocabulary
• atom
• Dalton’s atomic theory
Part A Completion
Use this completion exercise to check your understanding of the concepts and terms
that are introduced in this section. Each blank can be completed with a term, short
phrase, or number.
Elements are composed of tiny particles called
2
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Atoms of any one element are
1
.
1. _______________________
from those of any
2. _______________________
3
3. _______________________
by combining in whole-number ratios. Chemical reactions
4. _______________________
other element. Atoms of different elements can form
occur when atoms are
4
.
Part B True-False
Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT.
________ 5. Atoms of one element change into atoms of another element during
chemical reactions.
________ 6. Atoms combine in one-to-one ratios to form compounds.
________ 7. Atoms of one element are different from atoms of other elements.
Chapter 4 Atomic Structure
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Part C Matching
Match each description in Column B to the correct term in Column A.
Column A
Column B
________ 8. atom
a. an instrument used to generate images of individual
atoms
________ 9. scanning tunneling
microscope
b. Greek philosopher who was among the first to suggest
the existence of atoms
________ 10. John Dalton
c. the smallest particle of an element that retains its
identity in a chemical reaction
________ 11. Democritus
d. English chemist and schoolteacher who formulated a
theory to describe the structure and chemical reactivity
of matter in terms of atoms
Part D Questions and Problems
Answer the following questions in the space provided.
12. In what type of ratios do atoms combine to form compounds?
84
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13. How many copper atoms would you have to line up side by side to form a line
1 m long?
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Date ___________________
Class __________________
STRUCTURE OF THE NUCLEAR ATOM
4.2
Section Review
Objectives
• Identify three types of subatomic particles
• Describe the structure of atoms according to the Rutherford model
Vocabulary
• electrons
• cathode ray
• protons
• neutrons
• nucleus
Part A Completion
Use this completion exercise to check your understanding of the concepts and terms
that are introduced in this section. Each blank can be completed with a term, short
phrase, or number.
Dalton theorized that atoms are indivisible, but the discovery
1
of
particles changed this theory. Scientists now know that
2
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atoms are made up of electrons, which have a
3
,which have a positive charge; and
4
6
nucleus, which has a
3. _______________________
, which are
4. _______________________
5
5. _______________________
of the
who discovered the nucleus of the atom. The
7
charge, occupies a very small volume
of the atom. In contrast, the negatively charged
2. _______________________
charge;
neutral. The latter two particles are found in the
atom. It was
1. _______________________
8
occupy
6. _______________________
7. _______________________
8. _______________________
most of the volume of the atom.
Part B True-False
Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT.
______
9. According to Dalton’s atomic theory, atoms are composed of protons,
electrons, and neutrons.
______
10. Atoms of elements are electrically neutral.
______
11. The mass of an electron is equal to the mass of a neutron.
______
12. The charge on all protons is the same.
Chapter 4 Atomic Structure
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Date ___________________
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Part C Matching
Match each description in Column B to the correct term in Column A
Column A
Column B
________ 13. electrons
a. stream of electrons produced at the negative electrode
of a tube containing a gas at low pressure
________ 14. cathode ray
b. the central core of an atom, which is composed of
protons and neutrons
________ 15. protons
c. negatively charged subatomic particles
________ 16. neutrons
d. subatomic particles with no charge
________ 17. nucleus
e. positively charged subatomic particles
Part D Questions and Problems
Answer the following questions in the space provided.
18. Which subatomic particles are found in the nucleus of an atom?
19. Which subatomic particles are charged?
86
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20. Describe Rutherford’s model of the atom, including the location of protons,
neutrons, and electrons with respect to the nucleus. How does this model
explain the deflections of a beam of alpha particles aimed at a sheet of gold foil?
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DISTINGUISHING BETWEEN ATOMS
4.3
Section Review
Objectives
• Explain how isotopes differ from one another
• Use the atomic number and mass number of an element to find the numbers
of protons, electrons, and neutrons
• Calculate the atomic mass of an element from isotope data
Vocabulary
• atomic number
• mass number
• isotopes
• atomic mass unit (amu)
• atomic mass
• periodic table
• period
• group
Key Equations
• atomic number number of protons number of electrons
• number of neutrons mass number atomic number
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Part A Completion
Use this completion exercise to check your understanding of the concepts and terms
that are introduced in this section. Each blank can be completed with a term, short
phrase, or number.
1
The number of
atomic
2
in the nucleus of an atom is the
1. _______________________
of that element. Because atoms are electrically
2. _______________________
3
in an atom are equal.
3. _______________________
and neutrons in an atom is the mass
4. _______________________
neutral, the number of protons and
The total number of
4
number. Atoms of the same element are identical in most respects,
but they can differ in the number of
5
5. _______________________
in the nucleus. Atoms
6. _______________________
that have the same number of protons but different mass numbers
7. _______________________
are called
The
6
7
.
8. _______________________
of an element is the weighted average of the
9. _______________________
masses of the isotopes of that element. Each of the three known
isotopes of hydrogen has
8
proton(s) in the nucleus. The
most common hydrogen isotope has
mass number of
10
10. _______________________
9
neutrons. It has a
and is called hydrogen-1.
Chapter 4 Atomic Structure
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Part B True-False
Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT.
________ 11. The atomic number of an element is the sum of the protons and
electrons in an atom of that element.
________ 12. The atomic number of an atom is the total number of protons in an
atom of that element.
________ 13. An atom of nitrogen has 7 protons and 7 neutrons.
________ 14. Relative atomic masses are expressed in amus.
________ 15. The number of neutrons in the nucleus can be calculated by
subtracting the atomic number from the mass number.
Part C Matching
Match each description in Column B to the correct term in Column A
Column A
Column B
a. atoms that have the same number of protons but
different numbers of neutrons
________ 17. periodic table
b. weighted average mass of the atoms in a naturally
occurring sample of an element
________ 18. mass number
c. equals the number of neutrons plus the number of
protons in an atom
________ 19. group
d.
________ 20. isotopes
e. the number of protons in the nucleus of an atom of
an element
________ 21. atomic mass unit (amu)
f. an arrangement of elements according to similarities
in their properties
________ 22. atomic mass
g. a vertical column of elements in the periodic table
________ 23. period
h. a horizontal row of the periodic table
1
12
the mass of a carbon-12 atom
Part D Questions and Problems
Solve the following problem in the space provided.
24. Given the relative abundance of the following naturally occurring isotopes of
oxygen, calculate the average atomic mass of oxygen.
oxygen-16:
oxygen-17:
oxygen-18:
88
99.76%
0.037%
0.204%
Core Teaching Resources
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________ 16. atomic number
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Date ___________________
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ATOMIC STRUCTURE
Practice Problems
In your notebook, solve the following problems.
SECTION 4.1 DEFINING THE ATOM
1. According to Figure 5.2, 100,000,000 copper atoms would form a line 1 cm
long. How long would a line formed by 1 107 copper atoms be? Express
your answer in millimeters.
SECTION 4.2 STRUCTURE OF THE NUCLEAR ATOM
1. A sulfur-32 atom contains 16 protons, 16 neutrons, and 16 electrons. What is
the mass (in grams) of a sulfur-32 atom?
2. The mass of a neutron is 1.67 1024 g. Approximately what number of
neutrons would equal a mass of one gram?
3. Which statement is consistent with the results of Rutherford’s gold foil
experiment?
a. All atoms have a positive charge.
b. Atoms are mostly empty space.
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c. The nucleus of an atom contains protons and electrons.
d. Mass is spread uniformly throughout an atom.
SECTION 4.3 DISTINGUISHING BETWEEN ATOMS
1. How many protons are found in an atom of each of the following?
a. boron
c. neon
b. sulfur
d. lithium
2. Complete the table for the following elements.
Element
Number of
Protons
Manganese
25
Sodium
Bromine
Number of
Electrons
Actinium
Atomic
Number
Mass
Number
39
89
30
11
35
12
45
Yttrium
Arsenic
Number of
Neutrons
33
75
227
Chapter 4 Atomic Structure
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Class __________________
3. How many neutrons are in each atom?
a. 23
c. 81
11Na
35Br
b.
238
92 U
d.
19
9F
4. The two most abundant isotopes of carbon are carbon-12 (mass 12.00 amu)
and carbon-13 (mass 13.00 amu). Their relative abundances are 98.9% and
1.10%, respectively. Calculate the atomic mass of carbon.
5. Element X has two isotopes: X-100 and X-104. If the atomic mass of X is 101
amu, what is the relative abundance of each isotope in nature?
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Core Teaching Resources
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Name ___________________________
4
Date ___________________
Class __________________
ATOMIC STRUCTURE
Vocabulary Review
Match the correct vocabulary term to each numbered statement. Write the letter of the
correct term on the line.
Column A
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1
Column B
________ 1. defined as 12 the mass of a carbon-12 atom
a. isotopes
________ 2. central core of an atom, which contains most of the
atom’s mass
b. neutrons
________ 3. a vertical column of elements in the periodic table
c. atom
________ 4. subatomic particles with no charge
d. electrons
________ 5. positively charged subatomic particles
e. atomic number
________ 6. the smallest particle of an element that retains its
identity in a chemical reaction
f. atomic mass unit
________ 7. the number of protons in the nucleus of an element
g. group
________ 8. negatively charged subatomic particles
h. nucleus
________ 9. atoms with the same number of protons but
different numbers of neutrons
i. periodic table
________ 10. an arrangement of elements according to similarities
in their properties
j. protons
Chapter 4 Atomic Structure
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4
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ATOMIC STRUCTURE
Chapter Quiz
Fill in the word(s) that will make each statement true.
1. Dalton’s atomic theory included the idea that the atoms of
1
different elements can chemically combine in
ratios.
1. _______________________
2. An atom is the smallest particle of an element that retains its
2
identity in a
.
2. _______________________
3.
3
are subatomic particles with a negative charge.
4. The nucleus of an atom is composed of
4
3. _______________________
and protons.
5. A neutron has no charge, but its mass is almost the same as
5
that of a
.
6. The number of protons in an atom is called its
7. There are 10 neutrons and
oxygen-18.
7
6
5. _______________________
number. 6. _______________________
7. _______________________
8. Isotopes of an element have different numbers of neutrons.
8
They also have different
numbers.
8. _______________________
9. The total number of protons, neutrons, and electrons in an
9
atom of silver-109 (atomic number 47) is
.
9. _______________________
11. The horizontal rows of the periodic table are called
11
12. The elements in the periodic table are listed in order of
12 .
increasing
Core Teaching Resources
10. _______________________
.
11. _______________________
12. _______________________
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electrons in an atom of
10. The mass number of an element with 14 electrons and 16
10 .
neutrons is
92
4. _______________________
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4
Date ___________________
Class __________________
ATOMIC STRUCTURE
Chapter Test A
A. Matching
Match each description in Column B with the correct term in Column A. Write the
letter of the correct description on the line.
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Column A
Column B
________ 1. proton
a. the total number of protons and neutrons in the nucleus of
an atom
________ 2. atom
b. the weighted average mass of the atoms in a naturally
occurring sample of an element
________ 3. mass number
c.
________ 4. atomic mass unit
d. the number of protons in the nucleus of an element
________ 5. electron
e. atoms with the same number of protons but different
numbers of neutrons
________ 6. isotopes
f. negatively charged subatomic particle
________ 7. atomic number
g. the smallest particle of an element that retains its identity in
a chemical reaction
________ 8. atomic mass
h. a horizontal row of the periodic table
1
12
the mass of a carbon-12 atom
________ 9. period
i. subatomic particle with no charge
________ 10. neutron
j. positively charged subatomic particle
B. Multiple Choice
Choose the best answer and write its letter on the line.
________ 11. Which of the following is not a part of Dalton’s atomic theory?
a. All elements are composed of atoms.
b. Atoms of the same element are alike.
c. Atoms are always in motion.
d. Atoms that combine do so in simple whole-number ratios.
________ 12. The nucleus of an atom is
a. negatively charged and has a low density.
b. negatively charged and has a high density.
c. positively charged and has a low density.
d. positively charged and has a high density.
Chapter 4 Atomic Structure
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Date ___________________
Class __________________
________ 13. Dalton theorized that atoms are indivisible and that all atoms of an element
are identical. Scientists now know that
a. Dalton’s theories are completely correct.
b. atoms of an element can have different numbers of protons.
c. atoms are all divisible.
d. all atoms of an element are not identical but they all have the
same mass.
________ 14. The number of neutrons in the nucleus of an atom can be calculated by
a. adding together the numbers of electrons and protons.
b. subtracting the number of protons from the number of electrons.
c. subtracting the number of protons from the mass number.
d. adding the mass number to the number of protons.
________ 15. The sum of the protons and neutrons in an atom equals the
a. atomic number.
c. atomic mass.
b. number of electrons.
d. mass number.
________ 16. All atoms of the same element have the same:
a. number of protons.
c. mass number.
b. number of neutrons.
d. mass.
________ 17. Which of these statements is false?
a. Electrons have a negative charge.
b. Electrons have a mass of 1 amu.
c. The nucleus of an atom is positively charged.
d. The neutron is found in the nucleus of an atom.
________ 19. How do the isotopes hydrogen-2 and hydrogen-3 differ?
a. Hydrogen-3 has one more electron than hydrogen-2.
b. Hydrogen-3 has two neutrons.
c. Hydrogen-2 has three protons.
d. Hydrogen-2 has no protons.
________ 20. The number 80 in the name bromine-80 represents
a. the atomic number.
b. the mass number.
c. the sum of protons and electrons.
d. none of the above
________ 21. Which of these statements is not true?
a. Atoms of the same elements can have different masses.
b. The nucleus of an atom has a positive charge.
c. Atoms of isotopes of an element have different numbers of protons.
d. Atoms are mostly empty space.
94
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________ 18. An atom of an element with atomic number 48 and mass number 120 contains
a. 48 protons, 48 electrons, and 72 neutrons.
b. 72 protons, 48 electrons, and 48 neutrons.
c. 120 protons, 48 electrons, and 72 neutrons.
d. 72 protons, 72 electrons, and 48 neutrons.
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________ 22. Relative atomic masses are measured in
a. nanograms.
c. angstroms.
b. grams.
d. amus.
________ 23. If E is the symbol for an element, which two of the following symbols represent
isotopes of the same element?
1.
24
12E
2.
24
13E
a. 1 and 2
b. 3 and 4
3.
25
11E
4.
25
12E
c. 1 and 4
d. 2 and 3
C. Problems
Solve the following problem in the space provided. Show your work.
24. There are five naturally occurring isotopes of the element zinc. The relative
abundance and mass of each are as follows.
64
30Zn
48.89%, 63.929 amu
66
30Zn
27.81%, 65.926 amu
67
30Zn
4.11%, 66.927 amu
68
30Zn
18.57%, 67.925 amu
70
30Zn
0.62%, 69.925 amu
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Calculate the average atomic mass of zinc.
Chapter 4 Atomic Structure
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Date ___________________
Class __________________
25. Complete this table.
Atomic
Number
Mass
Number
Number of
Protons
9
Number of
Neutrons
Number of
Electrons
10
14
7
21
13
20
27
56
26
26. List the number of protons, neutrons, and electrons in each of the
following atoms.
Protons
Neutrons
Electrons
13
6C
10
4Be
20
10Ne
11
5B
D. Essay
Write a short essay to answer the following.
27. Explain how the atoms of one element differ from those of another element.
Then explain how the atoms of one isotope differ from those of other isotopes
of the same element.
96
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33
16S
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Name ___________________________
4
Date ___________________
Class __________________
ATOMIC STRUCTURE
Chapter Test B
A. Matching
Match each term in Column B with the correct description in Column A. Write the
letter of the correct term on the line.
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Column A
Column B
________ 1. the number of protons in the nucleus of an element
a. electron
________ 2. the smallest particle of an element that retains its identity in
a chemical reaction
b. mass number
________ 3. the total number of protons and neutrons in the nucleus of
an atom
c. atomic number
________ 4. a positively charged subatomic particle
d. atomic mass
________ 5. atoms with the same number of protons but different
numbers of neutrons
e. neutron
________ 6. a negatively charged subatomic particle
f. atomic mass unit
________ 7.
1
12
g. proton
the mass of a carbon-12 atom
________ 8. an arrangement of elements in which the elements are
separated into groups based on a set of repeating properties
h. isotopes
________ 9. a subatomic particle with no charge
i. atom
________ 10. the weighted average of the mass of the atoms in a naturally
occurring sample of an element
j. periodic table
B. Multiple Choice
Choose the best answer and write its letter on the line.
________ 11. Which of these statements is included in Dalton’s atomic theory?
a. Chemical reactions occur when atoms are separated, joined, or
rearranged.
b. Some but not all elements are composed of atoms.
c. Atoms of the same element can have different numbers of protons.
d. Atoms are divisible.
________ 12. Which of the following statements is correct?
a. Electrons are positively charged.
b. Protons are negatively charged.
c. Neutrons have no charge.
d. Atoms are positively charged.
Chapter 4 Atomic Structure
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Date ___________________
Class __________________
________ 13. Which of the following correctly lists the particles in order from least massive to
most massive?
a. proton, electron, hydrogen atom, helium atom
b. proton, helium atom, hydrogen atom, electron
c. hydrogen atom, electron, helium atom, proton
d. electron, proton, hydrogen atom, helium atom
________ 14. Which of the following statements is not consistent with the results obtained in
Rutherford’s gold foil experiment?
a. The nucleus of an atom is positively charged.
b. The nucleus of an atom contains almost all the mass of the atom.
c. Atoms are composed mainly of empty space.
d. Electrons are contained in the nucleus of an atom.
________ 15. The identity of an element can be determined on the basis of which of
the following?
a. the number of protons in an atom of the element
b. the number of neutrons in an atom of the element
c. the mass number of the element
d. the atomic mass of the element
________ 16. What is the atomic number and the mass number of an atom with 11 protons
and 12 neutrons?
a. atomic number 11 and mass number 12
b. atomic number 12 and mass number 11
c. atomic number 11 and mass number 23
d. atomic number 23 and mass number 12
________ 18. Which of the following statements is correct?
a. Each vertical column of elements in the periodic table is called a period.
b. The elements in any group of the periodic table have similar physical and
chemical properties.
c. Group 1A contains the elements hydrogen and helium.
d. In the modern periodic table, elements are listed in order of increasing
atomic mass.
________ 19. Isotopes of the same element have
a. the same number of protons but different numbers of neutrons.
b. the same number of protons but different numbers of electrons.
c. the same number of neutrons but different numbers of protons.
d. the same number of neutrons but different numbers of electrons.
________ 20. Which symbol correctly represents an element (D) whose atoms contain
15 protons and 20 neutrons?
a. 20
c. 35
15D
15D
15
b. 20D
d. 15
35D
98
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________ 17. An atom of hydrogen-2 contains
a. 2 protons, 2 electrons, and 2 neutrons.
b. 2 protons, 2 electrons, and 4 neutrons.
c. 1 proton, 1 electron, and 1 neutron.
d. 1 proton, 1 electron, and 2 neutrons.
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Date ___________________
Class __________________
________ 21. If Z is the symbol for an element, which pair among the following represents
isotopes of the same element?
51
50
a. 51
c. 50
25Z and 26Z
25Z and 27Z
51
50
51
b. 25Z and 25Z
d. 26Z and 50
25Z
________ 22. The relative abundance of each isotope of an element determines its
a. atomic number.
c. number of electrons.
b. atomic mass.
d. number of protons.
________ 23. Three isotopes of oxygen occur in nature: oxygen-16, oxygen-17, and oxygen-18.
If the atomic mass of oxygen is 15.9994, which of the three isotopes, if any, is the
most abundant?
a. oxygen-16
c. oxygen-18
b. oxygen-17
d. All are equally abundant.
________ 24. Element Z has two naturally occurring isotopes: Z-20 and Z-22. If the atomic mass
of Z is 21.5 amu, what is the relative abundance of each isotope in nature?
a. one Z-20 to one Z-22
c. two Z-20s to one Z-22
b. one Z-20 to two Z-22s
d. one Z-20 to three Z-22s
C. Problems
Solve the following problems in the space provided. Show your work.
25. The element argon contains three naturally occurring isotopes:
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36
18Ar
38
18Ar
40
18Ar
The relative abundances and atomic masses are 0.337% (mass 35.978 amu),
0.063% (mass 37.963 amu), and 99.600% (mass 39.962 amu), respectively.
Calculate the average atomic mass of argon.
26. List the numbers of protons, neutrons, and electrons in each of the following atoms.
Protons
Neutrons
Electrons
19
9F
27
13Al
40
18Ar
65
30Zn
108
47 Ag
Chapter 4 Atomic Structure
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Date ___________________
Class __________________
27. Complete the following table.
Atomic
Number
Mass
Number
Number of
Protons
Number of
Neutrons
Number of
Electrons
Symbol
24
12Mg
12
39
20
30
26
80
35Br
79
118
D. Essay
Write a short essay for the following.
28. Explain how the isotopes of one element are alike and how they are different.
Give at least two examples of each.
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100
Core Teaching Resources