Deck 2: Atoms and Radioactivity

Question 1

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 1

an atom

Question 2

The neutral atom always contains:

A)the same number of protons and neutrons
B)the same number of neutrons and electrons
C)the same number of protons and electrons
D)the same number of protons, neutrons and electrons

Answer 2

the same number of protons and electrons

Question 3

Which particle(s)are in the nucleus?

A)Protons only
B)Neutrons only
C)Protons and neutrons
D)Protons and electrons

Answer 3

Protons and neutrons

Question 4

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

A)first energy level
B)outermost energy level
C)nucleus
D)electrons

Question 5

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

Question 6

Mercury-202 has how many neutrons in its nucleus?

A)22
B)102
C)122
D)202

Question 7

Uranium-235 has how many protons in the nucleus?

A)92
B)143
C)235
D)51

Question 8

Adding one proton to the nucleus of an atom:

A)increases the atom ic number and the mass number by one unit
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

Question 9

Adding one neutron to the nucleus of an atom:

A)increases the atom ic number and the mass number by one unit
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

Question 10

The quantity (mass number - atomic number)provides:

A)the number of neutrons in a nucleus
B)the number of electrons in the atom
C)the number of protons in a nucleus
D)the combined number of all the neutrons and all the protons in a nucleus

Question 11

The mass number is:

A)the sum of protons + neutrons
B)the sum of protons + electrons
C)the sum of electrons + neutrons
D)the difference between neutrons and protons

Question 12

How many neutrons are in a neutral atom of Fe-56?

A)26
B)30
C)56
D)82

Question 13

Isotopes have the:

A)same number of protons but different number of electrons
B)same number of protons but different number of neutrons
C)same number of neutrons but different number of electrons
D)all of the above

Question 14

A hypothetical element contains three isotopes of mass 16.0 amu, 17.0 amu, and 18.0 amu with relative abundances of 20.0%, 50.0% and 30.0%, respectively. The average atomic mass is:

A)16.9 amu
B)17.1 amu
C)17.3 amu
D)17.5 amu

Question 15

Which of the following represents a pair of isotopes?

A)
B)
C)
D)O₂, O₃

Question 16

What is the correct symbol for the isotope of copper with a mass number of 63?

A)
B)
C)
D)

Question 17

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

A)Grams
B)Amus
C)Tons
D)Pounds

Question 18

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

Question 19

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

A)alpha particles
B)gamma rays
C)beta particles
D)neutrons

Question 20

The form of radioactivity that penetrates matter most easily is:

A)alpha particles
B)gamma rays
C)beta particles
D)protons

Question 21

The form of radioactivity that penetrates matter the least is:

A)alpha particles
B)gamma rays
C)beta particles
D)protons

Question 22

Form of radiation that has no mass:

A)alpha particles
B)beta particles
C)gamma rays
D)neutrons

Question 23

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

Question 24

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

Question 25

What protective shielding is sufficient for gamma rays?

A)Paper
B)Aluminium sheet
C)Lead sheet
D)All of the above

Question 26

What protective shielding is sufficient for alpha particles?

A)Paper
B)Aluminium sheet
C)Lead sheet
D)All of the above

Question 27

The correct symbol for the positron is:

A)
B)
C)
D)

Question 28

What radioactive particle is missing in the following nuclear reaction?

A)
B)
C)
D)

Question 29

What radioactive particle is missing in the following nuclear reaction?

A)
B)
C)
D)

Question 30

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

A)
B)
C)
D)

Question 31

When Americium-242 loses a beta particle the product of this process is:

A)
B)
C)
D)

Question 32

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

Question 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

Question 34

The half life of a specific Tc-99m is 6 hours. How much of an 192 mg sample will have decayed after 30 hours?

A)186 mg
B)160 mg
C)32 mg
D)6 mg

Question 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

Question 36

Using Table 2.7 in the text, identify which of the following radioactive nuclides would disappear first given the same initial quantities.

A)U-238
B)C-14
C)I-123
D)F-18

Question 37

Use Table 2.7 to determine which of the following isotopes will have the highest concentration after a long duration beginning with the same initial quantities.

A)H-3
B)P-32
C)Cr-51
D)F-18

Question 38

Different elements can contain the same atoms.

Question 39

Atoms are made up of smaller particles called molecules.

Question 40

The neutral atom contains equal numbers of protons and electrons.

Question 41

The neutral atom always contains equal numbers of protons and neutrons.

Question 42

The mass of the atom is almost all in the nucleus.

Question 43

A neutron has no charge and negligible mass.

Question 44

An electron has no charge and negligible mass.

Question 45

An atom of K-40 contains 40 neutrons.

Question 46

An atom of Pb-208 contains 126 neutrons.

Question 47

Isotopes always have the same atomic number.

Question 48

Isotopes always have the same mass number.

Question 49

All elements with atomic number 83 or greater are radioactive.

Question 50

All isotopes of elements with atomic 82 or lower are not radioactive.

Question 51

A positron is a positively charged electron.

Question 52

In beta decay the atomic number and mass number increase by 1.

Question 53

In alpha decay both the mass number and atomic number decrease.

Question 54

In positron decay the atomic number decreases by 1.

Question 55

After four half-lives the activity of a radioactive sample has decreased to one quarter of the initial value.

Question 56

After three half-lives 25 radioactive nuclei remain from an initial 200.

Question 57

After three half-lives 12.5% of the radioactive sample has decayed.

Question 58

A nucleotide with a long half-life will decay more rapidly than one with a short half-life.

Question 59

1 Ci = 3.7 × 10¹⁰ Bq

Question 60

Write the symbolic notation 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 ________

Question 61

Complete the following table:

Question 62

Write the symbol for the isotope of bismuth with 125 neutrons.

Question 63

The element rubidium (Rb)comprises two naturally occurring isotopes with mass numbers 85 (atomic mass 84.91 amu)and 87 (atomic mass 86.91 amu). If the atomic mass of the element is 85.47 amu, deduce which isotope is more abundant. Calculate the isotope distribution of Rb.

Question 64

The element magnesium (Mg)comprises three isotopes with mass numbers 24 (atomic mass 23.99 amu), 25 (atomic mass 24.99 amu)and 26 (atomic mass 25.98 amu), with the natural abundance of 78.99%, 10.00% and 11.01%, respectively. Calculate the atomic mass of Mg.

Question 65

Complete the following table.

Question 66

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) B) C) D) E) F) G)

Question 67

Write a nuclear equation for the following processes:

A)Bismuth-214 undergoes beta decay.
B)Thorium-230 decays to a radium isotope.
C)Magnesium-23 undergoes positron emission.

Question 68

What is the product of positron emission from F-18?

Question 69

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?

Question 70

The units of activity are known as the curie (Ci)and the becquerel (Bq). Write down the relationship between them.

Question 71

If a radioactive sample has an activity of 75 mCi. Calculate the activity in Bq. The units of activity are known as the curie (Ci)and the becquerel (Bq). Write down the relationship between them.

Question 72

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

Question 73

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

Question 74

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?

Question 75

In order for a radionuclide to be used for medical diagnosis it must have certain properties. Name two and explain why.

Question 76

Why is a radioactive nuclide which is an alpha emitter a bad choice in medical diagnostics or imaging?