Chemistry Matter and Change

Apply Six atoms of Element A combine with 15 atoms of Element B to produce
six compound particles. How many atoms of Elements A and B does each particle
contain? Are all of the atoms used to form compounds?

Anna Miller

Numerade Educator

03:25

Problem 6

Design a concept map that compares and contrasts the atomic ideas proposed
by Democritus and John Dalton.

Keenan Mintz

University of Miami

00:17

Problem 7

MAIN Idea Describe the structure of a typical atom. Identify where each
subatomic particle is located.

Anna Miller

Numerade Educator

02:43

Problem 8

Compare and contrast Thomson's plum pudding atomic model with
Rutherford's nuclear atomic model.

Keenan Mintz

University of Miami

00:29

Problem 9

Evaluate the experiments that led to the conclusion that electrons are
negatively charged particles found in all matter.

Anna Miller

Numerade Educator

01:53

Problem 10

Compare the relative charge and mass of each of the subatomic particles.

Keenan Mintz

University of Miami

00:25

Problem 11

Calculate What is the difference expressed in kilograms between the mass of
a proton and the mass of an electron?

Anna Miller

Numerade Educator

01:03

Problem 12

How many protons and electrons are in each atom?
a. radon $\quad$ b. magnesium

Keenan Mintz

University of Miami

Problem 13

An atom of an element contains 66 electrons. Which element is it?

Anna Miller

Numerade Educator

00:35

Problem 14

An atom of an element contains 14 protons. Which element is it?

Keenan Mintz

University of Miami

02:17

Problem 15

Challenge Do the atoms shown in the figure to the right have
the same atomic number?

David Collins

Numerade Educator

05:00

Problem 16

Determine the number of protons, electrons, and neutrons for isotopes b.-f. in the table above
Name each isotope, and write its symbol.

Keenan Mintz

University of Miami

00:52

Problem 17

Challenge An atom has a mass number of 55. Its number of neutrons is the sum of its
atomic number and five. How many protons, neutrons, and electrons does this atom have?
What is the identity of this atom?

Anna Miller

Numerade Educator

01:39

Problem 18

Boron (B) has two naturally occurring isotopes: boron-10 (abundance $=19.8 \%$
mass $=10.013$ amu) and boron-11 (abundance $=80.2 \%,$ mass $=11.009$ amu).
Calculate the atomic mass of boron.

Keenan Mintz

University of Miami

00:35

Problem 19

Challenge Nitrogen has two naturally occurring isotopes, $\mathrm{N}-14$ and $\mathrm{N}-15 .$ Its atomic
mass is 14.007 . Which isotope is more abundant? Explain your answer.

Anna Miller

Numerade Educator

00:58

Problem 20

MAIN Idea Explain how the type of an atom is defined.

Keenan Mintz

University of Miami

00:49

Problem 21

Recall Which subatomic particle identifies an atom as that of a particular
element?

Anna Miller

Numerade Educator

01:59

Problem 22

Explain how the existence of isotopes is related to the fact that atomic masses
are not whole numbers.

Keenan Mintz

University of Miami

00:45

Problem 23

Calculate Copper has two isotopes: $C u-63$ (abundance $=69.2 \%$
mass $=62.930$ amul and $\mathrm{Cu}-65$ (abundance $=30.8 \%,$ mass $=64.928$ amu).
Calculate the atomic mass of copper.

Anna Miller

Numerade Educator

01:44

Problem 24

Calculate Three magnesium isotopes have atomic masses and relative abun-
dances of 23.985 amu $(79.99 \%), 24.986$ amu $(10.00 \%),$ and 25.982$(11.01 \%) .$
Calculate the atomic mass of magnesium.

Keenan Mintz

University of Miami

Problem 25

MAIN Idea Explain how unstable atoms gain stability.

Anna Miller

Numerade Educator

01:06

Problem 26

State what quantities are conserved when balancing a nuclear reaction.

Keenan Mintz

University of Miami

00:46

Problem 27

Classify each of the following as a chemical reaction, a nuclear reaction,
or neither
\begin{equation}
\begin{array}{l}{\text { a. Thorium emits a beta particle. }} \\ {\text { b. Two atoms share electrons to form a bond. }} \\ {\text { c. A sample of pure sulfur emits heat energy as it slowly cools. }} \\ {\text { d. A piece of iron rusts. }}\end{array}
\end{equation}

Anna Miller

Numerade Educator

01:15

Problem 28

Calculate How much heavier is an alpha particle than an electron?

Keenan Mintz

University of Miami

00:29

Problem 29

Create a table showing how each type of radiation affects the atomic number
and the mass number of an atom.

Anna Miller

Numerade Educator

00:34

Problem 30

Who originally proposed the concept that matter is
composed of tiny, indivisible particles?

Keenan Mintz

University of Miami

00:38

Problem 31

Whose work is credited with being the beginning of
modern atomic theory?

Anna Miller

Numerade Educator

03:06

Problem 32

Distinguish between Democritus's ideas and Dalton's
atomic theory.

Keenan Mintz

University of Miami

00:15

Problem 33

Ideas and Scientific Methods Was Democritus's proposal of the existence of atoms based on scientific methods or ideas? Explain.

Anna Miller

Numerade Educator

01:29

Problem 34

Explain why Democritus was unable to experimentally
verify his ideas

Keenan Mintz

University of Miami

Problem 35

What was Aristotle's objection to the atomic theory?

Anna Miller

Numerade Educator

02:25

Problem 36

State the main points of Dalton's atomic theory using
your own words. Which parts of Dalton's theory were
later found to be erronous? Explain why.

Keenan Mintz

University of Miami

00:31

Problem 37

Conservation of Mass Explain how Dalton's atomic
theory offered a convincing explanation of the observation that mass is conserved in chemical reactions.

Anna Miller

Numerade Educator

01:13

Problem 38

Define matter and give two everyday examples

Keenan Mintz

University of Miami

00:16

Problem 39

What particles are found in the nucleus of an atom?
What is the charge of the nucleus?

Anna Miller

Numerade Educator

01:18

Problem 40

How was the overall charge distributed in the plum
pudding model?

Keenan Mintz

University of Miami

00:17

Problem 41

How did the charge distribution in the plum pudding
model affect alpha particles passing through an atom?

Anna Miller

Numerade Educator

01:15

Problem 42

Label the subatomic particles shown in Figure 4.22

Keenan Mintz

University of Miami

00:17

Problem 43

Arrange the following subatomic particles in order of increasing mass: neutron, electron, and proton.

Anna Miller

Numerade Educator

01:12

Problem 44

Explain why atoms are electrically neutral.

Keenan Mintz

University of Miami

01:02

Problem 45

What is the charge of the nucleus of element 89?

Ronald Prasad

Numerade Educator

00:53

Problem 46

Which particles account for most of an atom's mass?

Keenan Mintz

University of Miami

Problem 47

If you had a balance that could determine the mass of a
proton, how many clectrons would you need to weigh
on the same balance to measure the same mass as that of
a single proton?

Anna Miller

Numerade Educator

01:09

Problem 48

Cathode-Ray Tubes Which subatomic particle was dis-
covered by researchers working with cathode-ray tubes?

Keenan Mintz

University of Miami

Problem 49

What experimental results led to the conclusion that
electrons were part of all forms of matter?

Anna Miller

Numerade Educator

01:44

Problem 50

Cathode Ray Use the elements labeled in Figure 4.23
to explain the direction of a cathode ray inside a
cathode-ray tube.

Keenan Mintz

University of Miami

00:23

Problem 51

Briefly explain how Rutherford discovered the nucleus.

Anna Miller

Numerade Educator

01:25

Problem 52

Particle Deflection What caused the deflection of the
alpha particles in Rutherford's gold foil experiment?

Keenan Mintz

University of Miami

00:33

Problem 53

Charge of Cathode Rays How was an electric field
used to determine the charge of a cathode ray?

Anna Miller

Numerade Educator

01:39

Problem 54

Explain what keeps the electrons confined in the space
surrounding the nucleus.

Keenan Mintz

University of Miami

00:20

Problem 55

What is the approximate size of an atom?

Anna Miller

Numerade Educator

00:43

Problem 56

Visualizing Atoms What technique can be used to
visualize individual atoms?

Keenan Mintz

University of Miami

01:49

Problem 57

What are the strengths and weaknesses of Rutherford's
nuclear model of the atom?

Ronald Prasad

Numerade Educator

01:05

Problem 58

How do isotopes of a given element differ? How are they
similar?

Keenan Mintz

University of Miami

Problem 59

How is an atom's atomic number related to its number of
protons? To its number of electrons?

Anna Miller

Numerade Educator

00:39

Problem 60

How is the mass number related to the number of protons and neutrons an atom has?

Keenan Mintz

University of Miami

00:20

Problem 61

How can you determine the number of neutrons in an
atom if its mass number and its atomic number are
known.

Anna Miller

Numerade Educator

01:14

Problem 62

What do the superscript and subscript in the notation
$\stackrel{40}{19} \mathrm{K}$ represent?

Keenan Mintz

University of Miami

00:21

Problem 63

Standard Units Define the atomic mass unit. What
were the benefits of developing the atomic mass unit as a
standard unit of mass?

Anna Miller

Numerade Educator

01:09

Problem 64

Isotopes Are the following elements isotopes of each
other? Explain.
$$
_{12}^{24} \mathrm{Mg}_{12}^{25} \mathrm{Mg}_{12}^{26} \mathrm{Mg}
$$

Keenan Mintz

University of Miami

00:28

Problem 65

Does the existence of isotopes contradict part of Dalton's
original atomic theory? Explain.

Anna Miller

Numerade Educator

00:49

Problem 66

How many protons and electrons are contained in an
atom of element 44 ?

Keenan Mintz

University of Miami

Problem 67

Carbon A carbon atom has a mass number of 12 and
an atomic number of $6 .$ How many neutrons does it
have?

Anna Miller

Numerade Educator

00:56

Problem 68

Mercury An isotope of mercury has 80 protons and 120
neutrons. What is the mass number of this isotope?

Keenan Mintz

University of Miami

Problem 69

Xenon An isotope of xenon has an atomic number of
54 and contains 77 neutrons. What is the xenon isotope's

Anna Miller

Numerade Educator

00:29

Problem 70

If an atom has 18 electrons, how many protons does
it have?

Keenan Mintz

University of Miami

03:12

Problem 71

Sulfur Show that the atomic mass of the element sulfur
is 32.065 amu.

Vishal Sharma

Numerade Educator

03:19

Problem 72

Fill in the blanks in Table 4.6.

Keenan Mintz

University of Miami

00:39

Problem 73

How many electrons, protons, and neutrons are
contained in each atom?
\begin{equation}
\begin{array}{ll}{\text { a. }_{55}^{132} \mathrm{Cs}} & {\text { c. }_{69}^{163} \mathrm{Tm}} \\ {\text { b. }_{27}^{59} \mathrm{Co}} & {\text { d. }_{30}^{70} \mathrm{Zn}}\end{array}
\end{equation}

Anna Miller

Numerade Educator

02:08

Problem 74

How many electrons, protons, and neutrons are
contained in each atom?
\begin{equation}
\begin{array}{ll}{\text { a. gallium- } 69} & {\text { c. titanium- } 48} \\ {\text { b. fluorine- } 23} & {\text { d. } \text { tantalum }-181}\end{array}
\end{equation}

Keenan Mintz

University of Miami

00:33

Problem 75

For each chemical symbol, determine the number of
protons and electrons an atom of the element contains.
\begin{equation}
\begin{array}{ll}{\text { a. } V} & {\text { c. Ir }} \\ {\text { b. Mn }} & {\text { d. } S}\end{array}
\end{equation}

Anna Miller

Numerade Educator

View

Problem 76

Gallium, which has an atomic mass of 69.723 amu, has
two naturally occurring isotopes, Ga- 69 and Ga- $71 .$
Which isotope occurs in greater abundance? Explain.

Susan Hallstrom

Numerade Educator

Problem 77

Atomic Mass of Silver Silver has two isotopes:
$\stackrel{107}{47} \mathrm{Ag}$ which has a mass of 106.905 amu and a percent
abundance of 52.00$\%$, and 47
$\stackrel{109}{47} \mathrm{Ag}$, which has a mass of
108.905 amu and an percent abundance of 48.00$\%$
What is the atomic mass of silver?

Anna Miller

Numerade Educator

02:02

Problem 78

Data for chromium's four naturally occuring isotopes are
provided in Table 4.7 . Calculate chromium's atomic mass.

Keenan Mintz

University of Miami

Problem 79

What is radioactive decay?

Anna Miller

Numerade Educator

01:38

Problem 80

Why are some atoms radioactive?

Keenan Mintz

University of Miami

Problem 81

Discuss how radioactive atoms gain stability

Anna Miller

Numerade Educator

01:40

Problem 82

Define alpha particle, beta particle, and gamma ray

Keenan Mintz

University of Miami

00:27

Problem 83

Write the symbols used to denote alpha, beta, and
gamma radiation and give their mass and charge.

Anna Miller

Numerade Educator

00:36

Problem 84

What type of reaction involves changes in the nucleus of
an atom?

Keenan Mintz

University of Miami

Problem 85

Radioactive Emissions What change in mass number
occurs when a radioactive atom emits an alpha particle?
A beta particle? A gamma particle?

Anna Miller

Numerade Educator

00:43

Problem 86

What is the primary factor that determines whether an
nucleus is stable or unstable?

Keenan Mintz

University of Miami

00:16

Problem 87

Explain how energy loss and nuclear stability are related
to radioactive decay

Anna Miller

Numerade Educator

01:07

Problem 88

Explain what must occur before a radioactive atom stops
to undergo further radioactive decay

Keenan Mintz

University of Miami

05:36

Problem 89

Boron-10 emits alpha particles and cesium-137 emits
beta particles. Write balanced nuclear reactions for each
radioactive decay.

Vishal Sharma

Numerade Educator

02:12

Problem 90

Determine what was wrong with Dalton's theory and
provide the most recent version of the atomic structure.

Keenan Mintz

University of Miami

00:15

Problem 91

Cathode-Ray Tube Describe a cathode-ray tube and
how it operates.

Anna Miller

Numerade Educator

01:51

Problem 92

Subatomic Particles Explain how J. J. Thomson's determination of the charge-to-mass ratio of the electron led
to the conclusion that atoms were composed of subatomic particles.

Keenan Mintz

University of Miami

01:40

Problem 93

How did the actual results of Rutherford's gold foil experiment differ from the results he expected?

David Collins

Numerade Educator

00:42

Problem 94

If a nucleus contains 12 protons, how many electrons are
in the neutral atom? Explain.

Keenan Mintz

University of Miami

00:27

Problem 95

An atom's nucleus has 92 protons and its mass number is
235. How many neutrons are in the nucleus? What is the
name of the atom?

Anna Miller

Numerade Educator

04:03

Problem 96

Complete Table 4.8.

Keenan Mintz

University of Miami

Problem 97

Approximately how many times greater is the diameter
of an atom than the diameter of its nucleus? Knowing
that most of an atom's mass is contained in the nucleus,
what can you conclude about the density of the nucleus?

Anna Miller

Numerade Educator

00:56

Problem 98

Is the charge of a nucleus positive, negative, or zero?
The charge of an atom?

Keenan Mintz

University of Miami

00:25

Problem 99

Why are electrons in a cathode-ray tube deflected by
electric fields?

Anna Miller

Numerade Educator

00:55

Problem 100

What was Henry Moseley's contribution to the modern
understanding of the atom?

Keenan Mintz

University of Miami

00:16

Problem 101

What is the mass number of potassium- 39$?$ What is the
isotope's charge?

Anna Miller

Numerade Educator

01:14

Problem 102

Boron-10 and boron-11 are the naturally occurring isotopes of elemental boron. If boron has an atomic mass of
10.81 amu, which isotope occurs in greater abundance?

Keenan Mintz

University of Miami

00:30

Problem 103

Semiconductors Silicon is important to the semiconductor manufacturing industry. The three naturally
occuring isotopes of silicon are silicon-28, silicon-29,
and silicon-30. Write the symbol for each.

Anna Miller

Numerade Educator

02:17

Problem 104

Titanium Use Table 4.9 to calculate the atomic mass of
titanium.

Keenan Mintz

University of Miami

00:26

Problem 105

Describe how each type of radiation affects an atom's
atomic number and mass number.

Anna Miller

Numerade Educator

01:50

Problem 106

Relative Abundances Magnesium constitutes about 2$\%$
of Earth's crust and has three naturally occurring isotopes. Suppose you analyze a mineral and determine
that it contains the three isotopes in the following proportions: Mg- 24 (abundance = $79 \% ), \mathrm{Mg}-25$ (abundance $=10 \% ),$ and $\mathrm{Mg}-26$ (abundance = 11 $\%$ ). If your
friend analyzes a different mineral containing magnesium, do you expect her to obtain the same relative
abundances for each magnesium isotope? Explain your
reasoning.

Keenan Mintz

University of Miami

Problem 107

Radiation Identify the two types of radiation shown in
Figure 4.24. Explain your reasoning

Anna Miller

Numerade Educator

02:36

Problem 108

Formulate How were scientific methods used to determine the model of the atom? Why is the model considered a theory?

Keenan Mintz

University of Miami

00:20

Problem 109

Discuss What experiment led to the dispute of J. J.
Thomson's plum pudding atomic model? Explain your
answer.

Anna Miller

Numerade Educator

01:14

Problem 110

Apply Which is greater, the number of compounds or
the number of elements? The number of elements or the
number of isotopes? Explain.

Keenan Mintz

University of Miami

Problem 111

Analyze An element has three naturally occurring iso-
topes. What other information must you know in order
to calculate the element's atomic mass?

Anna Miller

Numerade Educator

01:48

Problem 112

Apply If atoms are primarily composed of empty space,
explain why you cannot pass your hand through a solid
object.

Keenan Mintz

University of Miami

Problem 113

Formulate Sketch a modern atomic model of a typical
atom and identify where each type of subatomic particle
would be located.

Anna Miller

Numerade Educator

02:41

Problem 114

Apply Indium has two naturally occurring isotopes
and an atomic mass of 114.818 amu. In $-113$ has a mass
of 112.904 amu and an abundance of 4.3$\%$ . What is
the identity and percent abundance of indium's other
isotope?

Keenan Mintz

University of Miami