Nuclear Chemistry

Question 1

In his experiments, he exposed certain salts—among them uranium salts—to sunlight for several hours, whereupon they phosphoresced.

Answer 1

Henri Becquerel

Question 2

Three kinds of radiation

Answer 2

alpha, beta, gamma

Question 3

helium nuclei

Answer 3

Alpha particles

Question 4

are electrons. Each has a charge of 21.

Answer 4

Beta particles

Question 5

are high-energy electromagnetic radiation.

Answer 5

Gamma rays

Question 6

the distance from one wave crest to the next.

Answer 6

wavelength

Question 7

the number of crests that pass a given point in one second.

Answer 7

frequency

Question 8

Electromagnetic radiation comes in packets; the smallest units are called

Answer 8

photons

Question 9

are electromagnetic radiation of very high frequency (and high energy).

Answer 9

Gamma rays

Question 10

are electromagnetic radiation of very high frequency (and high energy).

Answer 10

Gamma rays

Question 11

has frequencies (and energies) higher than those of visible light but less than those of gamma rays.

Answer 11

X-rays

Question 12

Materials that emit radiation (alpha, beta, or gamma) are called

Answer 12

radioactive

Question 13

A radiation emitting isotope of an element

Answer 13

Radioactive isotopes

Question 14

A reaction that changes atomic nuclei of elements
(usually to atomic nuclei of other elements)

Answer 14

Nuclear reaction

Question 15

The proton remains in the nucleus but the electron is emitted from it.

Answer 15

Beta emission

Question 16

The changing of one element into another is called

Answer 16

transmutation

Question 17

emits both an a particle and gamma rays

Answer 17

Polonium-210

Question 18

Is a particle that has the same mass as an electron, but a charge of 11 rather than 21.

Answer 18

Positron

Question 19

often accompanies a and b emissions

Answer 19

Gamma emission

Question 20

an extranuclear electron is captured by the nucleus and there reacts with a proton to form a neutron.

Answer 20

Electron capture

Question 21

The time it takes for one half of any sample of radioactive material to decay is called the

Answer 21

Half-life

Question 22

most of the radioactivity disappears
after _______ by that time, only _____ of the original remains

Answer 22

5 half-lives, 3%

Question 23

After ______ half-lives, less than _______ of the activity remains.

Answer 23

10, 0.1%

Question 24

The half-life of an isotope is independent of

Answer 24

temperature and pressure

Question 25

When these rays interact with matter, they usually knock electrons out of the electron cloud surrounding an atomic nucleus, thereby creating positively charged ions from neutral atoms.

Answer 25

Ionizing radiation

Question 26

Ionizing radiation is characterized by two physical measurements

Answer 26

Intensity and energy

Question 27

which is the number of particles or photons emerging per unit time

Answer 27

Intensity

Question 28

Instruments used to measure intensity

Answer 28

Geiger-Muller counter and proportional counter

Question 29

material called a phosphor that emits a unit of light for each alpha or beta particle or gamma ray that strikes it.

Answer 29

Scintillation counters

Question 30

A commonly used unit of radiation intensity is the

Answer 30

Curie

Question 31

much smaller, unit of radiation activity (intensity) is the

Answer 31

Becquerel

Question 32

beta particles have an energy range of

Answer 32

1 to 3 MeV

Question 33

the least penetrating; they can be stopped by several sheets of ordinary paper, by ordinary clothing, and by the skin

Answer 33

Alpha particles

Question 34

have greater penetrating power; They can penetrate several millimeters of bone or tissue.

Answer 34

Beta particles

Question 35

is the most penetrating of the three types of radiation. They can pass completely through the body

Answer 35

Gamma radiation

Question 36

when in the body, are more damaging, however

Answer 36

Alpha particles

Question 37

are a measure of the energy delivered by a radiation source and are, therefore, a measure of exposure to a particular form of radiation.

Answer 37

Roentgens

Question 38

which stands for radiation absorbed dose, is a measure of the radiation absorbed from a radiation source.

Answer 38

Rad

Question 39

SI unit of rad

Answer 39

Gray = 100 rad

Question 40

which stands for roentgen equivalent for man, is a measure of the effect of the radiation when a person absorbs 1 roentgen.

Answer 40

Rem

Question 41

SI unit for rem

Answer 41

sievert = 100 rem

Question 42

Naturally occurring radiation

Answer 42

background radiation

Question 43

is the most widely used aspect of nuclear medicine.

Answer 43

Medical imaging

Question 44

This method is based on the property that certain isotopes (such as carbon-11 and fluorine-18) emit positrons

Answer 44

Positron emission tomography

Question 45

is used in the treatment of prostate cancer.

Answer 45

Iodine-25

Question 46

The fusion of two hydrogen nuclei into a helium nucleus liberates a very large amount of energy in the form of photons

Answer 46

Fusion

Question 47

Uncontrolled fusion is employed in the

Answer 47

Hydrogen bomb

Question 48

are artificial and have been prepared by a fusion process in which heavy nuclei are bombarded with light ones.

Answer 48

Transuranium elements

Question 49

Transuranium elements

Answer 49

elements with atomic numbers greater than 92

Question 50

fragmentation of large nuclei into smaller pieces

Answer 50

Nuclear fission

Question 51

The most important product of this nuclear decay is energy, which results because the products have less mass than the starting materials.

Answer 51

Atomic energy

Question 52

If even one of these neutrons produces a new fission, the process becomes a self-propagating _______ that continues at a constant rate.

Answer 52

Chain reaction

Question 53

is the combining (fusing) of two lighter nuclei to form a heavier nucleus.

Answer 53

Nuclear fusion

Question 54

results from the bombardment of nuclei by neutrons, protons, or other nuclei.

Answer 54

nuclear transmutation

Question 55

like charges repel and unlike charges attract one another.

Answer 55

Coulomb's law

Question 56

The principal factor that determines whether a nucleus is stable is the

Answer 56

neutron to proton ratio

Question 57

The numbers 2, 8, 20, 50, 82, and 126 are called

Answer 57

magic numbers

Question 58

Rules in predicting nuclear stability

Answer 58

1. Magic numbers for proton and neutrons 2. Even numbers of proton and neutron are more stable than odd numbers 3. All isotopes with atomic number higher than 83 are radioactive

Question 59

The stable nuclei are located in an area of the graph known as the

Answer 59

belt of stability

Question 60

the energy required to break up a nucleus into its component protons and neutrons.

Answer 60

Nuclear binding energy

Question 61

which is a general term for the protons and neutrons in a nucleus.

Answer 61

nucleons

Question 62

The difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons is called

Answer 62

mass defect

Question 63

a sequence of nuclear reactions that ultimately result in the formation of a stable isotope

Answer 63

radioactive decay series

Question 64

uses electric and magnetic fields to increase the kinetic energy of charged species so that a reaction will occur

Answer 64

Particle accelerator

Question 65

The first nuclear fission reaction to be studied was that of

Answer 65

Uranium-235

Question 66

the minimum mass of fissionable material required to generate a self-sustaining nuclear chain reaction

Answer 66

critical mass

Question 67

Most of the nuclear reactors in the United States are

Answer 67

light water reactors

Question 68

substances that can reduce the kinetic energy of neutrons.

Answer 68

moderators

Question 69

it eliminates the need for building expensive uranium enrichment facilities.

Answer 69

Heavy water reactors

Question 70

uses uranium fuel, but unlike a conventional nuclear reactor, it produces more fissionable materials than it uses

Answer 70

Breeder reactor

Question 71

are dangerous radioactive isotopes with long half-lives

Answer 71

Strontium-90

Question 72

used as a nuclear fuel and produced in breeder reactors, is one of the most toxic substances known.

Answer 72

Plutonium-239

Question 73

fusion reactions take place only at very high temperatures, they are often called

Answer 73

thermonuclear reactions

Question 74

state of matter, a gaseous mixture of positive ions and electrons

Answer 74

plasma

Question 75

Isotopes, especially radioactive isotopes that are used to trace the path of the atoms of an element in a chemical or biological process

Answer 75

tracers

Question 76

molecular fragments having one or more unpaired electrons; they are usually short lived and highly reactive.

Answer 76

radicals