## Instant Download with all chapters and Answers

Sample Chapters

***you will get test bank in PDF in best viewable format after buy***

General, Organic, and Biological Chemistry: An Integrated Approach (Frost)

Chapter 2 Atoms and Radioactivity

Multiple-Choice

1) Mercury-202 has how many neutrons in its nucleus?

A) 22

B) 102

C) 122

D) 202

Answer: C

Section: 2-2

2) Cobalt is element 27. Cobalt-60 is used in the medical treatment of cancer. How many

neutrons and protons are contained in the nucleus of this isotope?

A) 27 neutrons, 33 protons

B) 33 neutrons, 27 protons

C) 27 neutrons, 27 protons

D) 33 neutrons, 33 protons

Answer: B

Section: 2-2

3) The smallest particle of an element that can be identified as that element is:

A) a proton

B) a neutron

C) a molecule

D) an atom

Answer: A

Section: 2-1

4) Two atoms must represent the same element if they both have the same:

A) number of electron shells

B) atomic number

C) number of neutrons

D) atomic mass

Answer: B

Section: 2-1

5) Which one of the following carries no electrical charge?

A) An electron

B) A proton

C) A neutron

D) A cation

Answer: C

Section: 2-1

2

6) Almost all of the mass of an atom exists in its:

A) first energy level

B) outermost energy level

C) nucleus

D) electrons

Answer: C

Section: 2-1

7) Adding one proton to the nucleus of an atom:

A) converts it to an atom of a different element

B) increases its atomic mass by one unit, but does not change its atomic number

C) increases its atomic number by one unit but does not change its atomic mass

D) does not change either its atomic number or its atomic mass

Answer: A

Section: 2-2

8) The quantity (mass number – atomic number) provides:

A) the number of neutrons in a nucleus

B) the number of electrons in the first energy level

C) the number of protons in a nucleus

D) the combined number of all the neutrons and all the protons in a nucleus

Answer: A

Section: 2-2

9) Which subatomic particle contributes least to the mass of the atom?

A) Proton

B) Neutron

C) Electron

D) All of these contribute equally.

Answer: C

Section: 2-1

10) What are the number of neutrons in a neutral atom of Ar-40?

A) 18

B) 22

C) 40

D) 58

Answer: B

Section: 2-2

3

11) Which of the following represents a pair of isotopes?

A)

C

14

6

, N

14

7

B)

H

1

1

, H

2

1

C)

S

32

16

,

2

S

32

16

ï€

D) O2, O3

Answer: B

Section: 2-3

12) The element rhenium (Re) exists as two stable isotopes and 18 unstable isotopes. Rhenium185 (185Re) has in its nucleus:

A) 75 protons, 75 neutrons

B) 75 protons, 130 neutrons

C) 130 protons, 75 neutrons

D) 75 protons, 110 neutrons

Answer: D

Section: 2-3

13) The masses on the periodic table are expressed in what units?

A) Grams

B) Amu’s

C) Tons

D) Pounds

Answer: B

Section: 2-3

14) A thimble of water contains 4.0 Ã— 1021 molecules. The number of moles of H2O is:

A) 2.4 Ã— 1045

B) 6.6 Ã— 10-3

C) 6.6 Ã— 10-23

D) 2.4 Ã— 1023

Answer: B

Section: 2-4

15) What is the mass of 3.61 moles of Ca?

A) 0.090 g

B) 144 g

C) 40.0 g

D) 150 g

Answer: B

Section: 2-4

4

16) How many electrons are in the second energy level for an atom of N?

A) 5

B) 6

C) 4

D) 8

Answer: A

Section: 2-5

17) How many electrons can be contained in the first energy level?

A) 2

B) 8

C) 10

D) 18

Answer: A

Section: 2-5

18) How many electrons can be contained in the second energy level?

A) 2

B) 8

C) 10

D) 18

Answer: B

Section: 2-5

19) An atom of phosphorous has how many valence electrons?

A) 4

B) 5

C) 6

D) 8

Answer: B

Section: 2-5

20) An atom of chlorine has how many valence electrons?

A) 2

B) 4

C) 6

D) 7

Answer: D

Section: 2-5

21) Which of the following elements contains 6 valence electrons?

A) Si

B) P

C) S

D) Cl

Answer: C

Section: 2-5

5

22) Which of the following elements has a filled valence shell?

A) Ne

B) P

C) Se

D) O

Answer: A

Section: 2-5

23) The element Silicon has how many electrons in each of its energy levels?

A) 2, 8, 4

B) 2, 6, 4

C) 3, 5, 7

D) 2, 8, 6

Answer: A

Section: 2-5

24) Of the following, the radioisotope most useful in treating disorders of the thyroid gland is:

A) C-14

B) Tc-99m

C) U-238

D) I-131

Answer: D

Section: 2-6

25) Made up of helium nuclei traveling at 5-7% speed of light:

A) alpha particles

B) gamma rays

C) beta particles

D) neutrons

Answer: A

Section: 2-6

26) The form of radioactivity that penetrates matter most easily is:

A) alpha particles

B) gamma rays

C) beta particles

D) protons

Answer: B

Section: 2-6

27) Made up of electrons from the nucleus traveling at 90-95% speed of light:

A) alpha particles

B) gamma rays

C) beta particles

D) neutrons

Answer: C

Section: 2-6

6

28) The radioactive particles, alpha, beta and gamma ray, are called ionizing radiation because,

as they pass through an object, they:

A) repel ions

B) knock electrons off atoms or molecules in their path

C) decay into ions

D) attract ions

Answer: B

Section: 2-6

29) What radioactive particle is missing in the following nuclear reaction?

Mo 98

42

+ ________ â†’

Mo 99

42

A)

n

1

0

B)

e

0

ï€1

C)

He 4

2

D) p

Answer: A

Section: 2-7

30) What radioactive particle is missing in the following nuclear reaction?

Mo 99

42

â†’

Tc 99m

43

+ ________

A)

n

1

0

B)

e

0

ï€1

C)

He 4

2

D)

p

1

1

Answer: B

Section: 2-7

31) When Phosphorous-30 loses a positron what is the product of this radioactive decay?

A)

Si 30

14

B)

S

30

16

C)

S

31

16

D)

P

31

15

Answer: A

Section: 2-7

7

32) The amount of a radioisotope that remains after two half-lives have passed is:

A) 98%

B) 75%

C) 50%

D) 25%

Answer: D

Section: 2-8

33) The half life of a specific radionuclide is 8 days. How much of an 80 mg sample will be left

after 24 days?

A) 40 mg

B) 20 mg

C) 10 mg

D) 2.7 mg

Answer: C

Section: 2-8

34) In order to have 1/16 of a radioactive sample left how many half lives must the sample go

through to reach this amount?

A) 3

B) 4

C) 5

D) 6

Answer: B

Section: 2-8

35) A fossil found in a cave was found to have a Carbon-14 ratio to carbon of 1/ 32 of a live

object. If the half life of Carbon-14 is 5730 yrs, how old is the object?

A) 5730 yrs

B) 28,650 yrs

C) 34,480 yrs

D) 17,190 yrs

Answer: B

Section: 2-8

8

Short Answer

1) Write the symbolic notation (

X

A

Z

) for the following information.

A) 20 protons, 20 electrons, 20 neutrons _______________

B) 16 protons, 16 electrons, 16 neutrons _______________

C) 30 protons, 30 electrons, 35 neutrons _______________

D) 92 protons, 92 electrons, 146 neutrons _______________

Answer:

Ca 40

20

;

S

32

16

;

Br 65

35

;

U

238

92

Section: 2-2

2) Complete the following table:

Symbol Atomic # Mass # #p #n #e

I

131

53 ________ ________ ________ ________ 53

________ 43 99 43 ________ 43

Cl 37

17 ________ ________ 17 20 ________

________ 26 56 ________ ________ 23

Answer: Line 1: 53, 131, 53, 78

Line 2:

Tc 99

43

, 56

Line 3: 17, 37, 17

Line 4:

Fe 56

26

, 26, 30

Section: 2-2

3) Express the following in exponential form:

A) 5765

B) 0.000365

C) 102,000

D) 0.00000240

E) 602,000,000,000

F) 2000

Answer: A) 5.765 Ã— 103; B) 3.65 Ã— 10-4; C) 1.02 Ã— 105; D) 2.40 Ã— 10-6;

E) 6.02 Ã— 1011; F) 2 Ã— 103

Section: 2-4

9

4) Rewrite the following as ordinary numbers:

A) 6.75 x 105

B) 4.66 x 10-4

C) 2.020 x 103

D) 1.11 x 10-2

E) 23 x 10-5

Answer: A) 675000; B) 0.000466; C) 2020.; D) 0.00111; E) 0.000023

Section: 2-4

5) Perform the following mathematical operations. Give the answer with the proper number of

significant figures.

A) (2.45 Ã— 105) (5.6 Ã— 104) =

B) (7.5 Ã— 107) Ã· (8.566 Ã— 105) =

C) (3.45 Ã— 10-9) + (0.326 Ã— 10-9) =

Answer: A) 1.4 Ã— 1010; B) 88; C) 3.78 Ã— 10-9

Section: 2-4

6) Complete the following equations with the symbol for the atom or particle represented by the

blank space. Show the mass numbers and atomic numbers of the isotopes formed or the symbols

of the subatomic particles:

A)

Po 210

84

â†’ ________ +

Pb 206

82

B)

Pa 234

91

â†’ ________ +

e

0

ï€1

C) ________ â†’

U

236

92

+

He 4

2

D)

H

2

1

+

H

2

1

â†’

He 3

2

+ ________

E)

U

233

92

+

n

1

0

â†’

Sb 133

51

+ ________ + 2

n

1

0

F)

I

122

53

â†’

Xe 122

54

+ ________

G)

S

32

16

+

n

1

0

â†’

p

1

1

+ ________

Answer: A)

He 4

2

; B)

U

234

92

; C)

Th 240

94

; D)

n

1

0

; E)

Nb 98

41

; F)

e

0

ï€1

; G)

P

32

15

Section: 2-6

7) Write a nuclear equation for the following processes:

A) Bismuth-214 undergoes beta decay

B) Thorium-230 decays to a radium isotope

Answer: A)

Bi 214

83

â†’

e

0

ï€1

+ +

Po 213

84

; B)

Th 230

90

â†’

He 4

2

+2 +

Ra 226

88

Section: 2-6

10

8) You obtain a new sample of cobalt-60, half-life 5.25 years, with a mass of 400 mg. How much

cobalt-60 remains after 15.75 years?

Answer: 50 mg

Section: 2-8

9) Why can’t we use Carbon-14 dating techniques to date the age of a dinosaur bone?

Answer: Because after 10 half lives there is not enough C-14 left to measure it is less than 0.1 %

of the original value and dinosaurs lived over one billion years ago.

Section: 2-8

10) A 100-mg technetium-99m sample is used in a medical study. How much of the Technetium99m sample remains after 24 hours? The half-life of Tc-99m is 6 hours.

Answer: 24 hours/6 hours = 4 half lives; 100 mg â†’ 50 mg â†’ 25 mg â†’ 12.5 mg â†’ 6.25 mg

Section: 2-8

11) Krypton-81m is used for lung ventilation studies. Its half-life is 13 seconds. How long does it

take the activity of this isotope to reach one-quarter of its original value?

Answer: 1 â†’ 1/2 â†’ 1/4, so that is two half lives; therefore 26 secs

Section: 2-8

12) In order for a radionuclide to be used for medical diagnosis it must have certain properties.

Name two and explain why.

Answer: They must have a short half life in order to disappear from the body as soon as possible

and they should either be a beta or gamma ray emitter.

Section: 2-9