Introductory Chemistry: A Foundation

Steven S. Zumdahl, Donald J. DeCoste

Chapter 4

Chemical Foundations: Elements, Atoms, and lons - all with Video Answers

Educators

Chapter Questions

Problem 1

Knowing the number of protons in the atom of a neutral element enables you to determine which of the following?
a. the number of neutrons in the atom of the neutral element
b. the number of electrons in the atom of the neutral element
c. the name of the element
d. two of the above
e. none of the above
Explain.

Lottie Adams

Lottie Adams

Numerade Educator

Problem 2

The average mass of a carbon atom is $12.011 .$ Assuming you could pick up one carbon atom, what is the chance that you would randomly get one with a mass of $12.011 ?$
a. $0 \%$
d. $12.011 \%$
b. $0.011 \%$
e. greater than $50 \%$
c. about $12 \%$
f. none of the above
Explain.

Lottie Adams

Numerade Educator

Problem 3

How is an ion formed?
a. by either adding or subtracting protons from the atom
b. by either adding or subtracting neutrons from the atom
c. by either adding or subtracting electrons from the atom
d. all of the above
e. two of the above
Explain.

Lottie Adams

Numerade Educator

Problem 4

The formula of water, $\mathrm{H}_{2} \mathrm{O},$ suggests which of the following?
a. There is twice as much mass of hydrogen as oxygen in each molecule.
b. There are two hydrogen atoms and one oxygen atom per water molecule.
c. There is twice as much mass of oxygen as hydrogen in each molecule.
d. There are two oxygen atoms and one hydrogen atom per water molecule.
e. Two of the above.
Explain.

Lottie Adams

Numerade Educator

Problem 5

The vitamin niacin (nicotinic acid, $C_{6} H_{5} N O_{2}$ ) can be isolated from a variety of natural sources, such as liver, yeast, milk, and whole grain. It also can be synthesized from commercially available materials. Which source of nicotinic acid, from a nutritional view, is best for use in a multivitamin tablet? Why?

Lottie Adams

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Problem 6

One of the best indications of a useful theory is that it raises more questions for further experimentation than it originally answered. How does this apply to Dalton's atomic theory? Give examples.

Lottie Adams

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Problem 7

Dalton assumed that all atoms of the same element are identical in all their properties. Explain why this assumption is not valid.

Mehrnaz Siavoshi

Mehrnaz Siavoshi

Numerade Educator

Problem 8

How does Dalton's atomic theory account for the law of constant composition?

Lottie Adams

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Problem 9

Which of the following is true about the state of an individual atom?
a. An individual atom should be considered to be a solid.
b. An individual atom should be considered to be a liquid.
c. An individual atom should be considered to be a gas.
d. The state of the atom depends on which element it is.
e. An individual atom cannot be considered to be a solid, liquid, or gas.
For choices you did not pick, explain what you feel is wrong with them, and justify the choice you did pick.

Lottie Adams

Numerade Educator

Problem 10

These questions concern the work of J.J. Thomson:
a. From Thomson's work, which particles do you think he would feel are most important in the formation of compounds (chemical changes) and why?
b. Of the remaining two subatomic particles, which do you place second in importance for forming compounds and why?
c. Come up with three models that explain Thomson's findings and evaluate them. To be complete you should include Thomson's findings.

Lottie Adams

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Problem 11

Heat is applied to an ice cube until only steam is present. Draw a sketch of this process, assuming you can see it at an extremely high level of magnification. What happens to the size of the molecules? What happens to the total mass of the sample?

Lottie Adams

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Problem 12

What makes a carbon atom different from a nitrogen atom? How are they alike?

Lottie Adams

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Problem 13

Hundreds of years ago, alchemists tried to turn lead into gold. Is this possible? If not, why not? If yes, how would you do it?

Lottie Adams

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Problem 14

Chlorine has two prominent isotopes, $^{3} \mathrm{Cl}$ and $^{35} \mathrm{Cl}$. Which is more abundant? How do you know?

Lottie Adams

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Problem 15

Differentiate between an atomic element and a molecular element. Provide an example and microscopic drawing of each.

Lottie Adams

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Problem 16

Science often develops by using the known theories and expanding, refining, and perhaps changing these theories. As discussed in Section 4.5, Rutherford used Thompson's ideas when thinking about his model of the atom. What if Rutherford had not known about Thompson's work? How might Rutherford's model of the atom have been different?

David Collins

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Problem 17

Rutherford was surprised when some of the $\alpha$ particles bounced back. He was surprised because he was thinking of Thompson's model of the atom. What if Rutherford believed atoms were as Dalton envisioned them? What do you suppose Rutherford would have expected, and what would have surprised him?

David Collins

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Problem 18

It is good practice to actively read the textbook and to try to verify claims that are made when you can. The following claim is made in your textbook: " ... if the nucleus were the size of a grape, the electrons would be about one mile away on average." Provide mathematical support for this statement.

Lottie Adams

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Problem 19

Why is the term "sodium chloride molecule" incorrect but the term "carbon dioxide molecule" is correct?

Lottie Adams

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Problem 20

Both atomic elements and molecular elements exist. Are there such entities as atomic compounds and molecular compounds? If so, provide an example and microscopic drawing. If not, explain why not.

Lottie Adams

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Problem 21

Now that you have gone through Chapter 4, go back to Section 4.3 and review Dalton's Atomic Theory. Which of the premises are no longer accepted? Explain your answer.

Lottie Adams

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Problem 22

Write the formula for each of the following substances, listing the elements in the order given.
a. List the phosphorus atom first.
b. a molecule containing two boron atoms and six hydrogen atoms
c. a compound containing one calcium atom for every two chlorine atoms
d. List the carbon atom first.
e. a compound containing two iron atoms for every three oxygen atoms
f. a molecule containing three hydrogen atoms, one phosphorus atom, and four oxygen atoms

Lottie Adams

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Problem 23

Use the following figures to identify the element or ion. Write the symbol for each, using the $_{2}^{4} X$

Lottie Adams

Numerade Educator