Chapter 21: NUCLEAR CHEMISTRY

Radioactive decay chain

________- a series of nuclear reactions that begins with an unstable nucleus and terminates with a stable one; also known as nuclear disintegration series.

RBE

________ (Relative Biological Effectiveness): The radiation dose is multiplies by a factor that measures the relative damages caused by the radiation.

Nuclear Transmutations

________- occurs when a nucleus is struck by a neutron or by another nucleus which causes it to change its identity.

Free Radical

________- a substance with one or more unpaired electrons, as seen in the Lewis structure shown in the margin.

fuel elements

When the ________ are removed from the reactor, they are initially very radioactive.

Nucleons

________- protons and neutrons; the two types of subatomic particles that reside in the nucleus.

Cyclotron

________- in this device, charged particles move in a spiral path within two D- shaped electrodes.

Primary Coolant

________- a substance that transports the heat generated by the nuclear chain reaction away from the reactor core.

small quantity

When a(n) ________ of a radioisotope is mixed with the naturally occurring stable isotopes of the same element, all the isotopes go through the same reactions together.

Radionuclides

________- nuclides that are radioactive.

neptunium

Elements 93 (________, Np) and 94 (plutonium, Pu) were produced in 1940 by bombarding uranium- 238 with neutrons:

Radioactive decay

________- a first- order kinetic process.

Radiocarbon

________ dating- the technique of dating when carbon- 14 is used in radiometric dating.

Fission

________: Happens when heavy nuclei gain stability and therefore give off energy if they are fragmented into two midsized nuclei.

Synchrotron

________- in this device, the magnetic fields are synchronized so that the particle moves in a circular rather than a spiral path.

Gray

________ (Gy)- the SI unit of absorbed dose, corresponds to the absorption of 1 J of energy per kilogram of tissue.

Fusion

________ is appealing as an energy source because of the availability of light isotopes on Earth and because ________ products are generally not radioactive.

Curie

________ (Ci)- an older unit of activity, defined as 3.7 x 10^10 disintegrations per second, which is the rate of decay of 1 g of radium.

Radioisotopes

________- atoms containing radionuclides.

moderator

The reactor operates without a(n) ________, which means the neutrons used are not slowed down.

Nuclide

________- a nucleus containing a specified number of protons and neutrons.

Positron emission

________ has the effect of converting a proton to a neutron, thereby decreasing the atomic number of the nucleus by 1 while not changing the mass number:

Rad

________ (Radiation Absorbed Dose)- corresponds to the absorption of 1 X 10^- 2 J of energy per kilogram of tissue.

Cobalt

________- 60, which is used in cancer radiation therapy, is produced by neutron capture.

Control Rods

________- composed of materials that absorb neutrons, such as boron- 10 or an alloy of silver, indium, and cadmium.

Isotopes

________- atoms with the same atomic number but different mass numbers.

Electron capture

________, like positron emission, has the effect of converting a proton to a neutron:

spontaneously decomposes

When a nucleus ________ in this way, it is said to be radioactive and to have decayed or to have undergone radioactive decay.

Strong nuclear force

________- a strong force of attraction at distances, existing between nucleons.

Mass Defect

________- the mass difference between a nucleus and its constituent nucleons.

Radiometric

________ dating- the method of dating objects based on their isotopes and isotope abundances.

International Union

________ for Pure and Applied Chemistry (IUPAC)- the international body that authorizes names of new elements after their experimental discovery and confirmation.

nuclear disintegration

It is defined as one ________ per second.

Nuclear fission

________ is the process used to generate energy in nuclear power plants.

Thermonuclear Reactions

________- also known as Fusion Reactions.

Critical Mass

________- the amount of fissionable material large enough to maintain a chain reaction with a constant rate of fission.

Nuclear Binding Energies

________- the energy required to separate a nucleus into its individual nucleons.

Alpha particles

________ and other positively charged particles must move ver y fast to overcome the electrostatic repulsion between them and the target nucleus.

Positron

________- is a particle that has the same mass as an electron (thus, we use the letter e and superscript 0 for the mass) but the opposite charge (represented by the +1 subscript)

Nuclear power plants

________ use nuclear fission to generate energy.

order process

A first- ________ has a characteristic half- life, which is the time required for half of any given quantity of a substance to react.

radioisotope

Because the ________ can be used to trace the path of the element, it is called a radiotracer.

Moderator

________- it functions to slow down the neutrons (to speeds of a few kilometers per second) so that they can be captured more readily by the fissionable nuclei.

Positron emission

________ causes the atomic number of the reactant in this equation to decrease from 6 to 5.

Nuclear transmutations

________ have been used to produce the elements with atomic number above 92, collectively known as the transuranium elements because they follow uranium in the periodic table.

radionuclides

However, ________ are unstable and spontaneously emit particles and electromagnetic radiation.

Nucleons

protons and neutrons; the two types of subatomic particles that reside in the nucleus

Mass number

the total number of nucleons in the nucleus

Isotopes

atoms with the same atomic number but different mass numbers

Nuclide

a nucleus containing a specified number of protons and neutrons

Radionuclides

nuclides that are radioactive

Radioisotopes

atoms containing radionuclides

Beta Radiation

consists of streams of beta particles, which are high-speed electrons emitted by an unstable nucleus

Gamma Radiation

consists of high-energy photons (that is, electromagnetic radiation of very short wavelength)

Strong nuclear force

a strong force of attraction at distances, existing between nucleons

Radioactive decay chain

a series of nuclear reactions that begins with an unstable nucleus and terminates with a stable one; also known as nuclear disintegration series

Nuclear Transmutations

occurs when a nucleus is struck by a neutron or by another nucleus which causes it to change its identity

Cyclotron

in this device, charged particles move in a spiral path within two D-shaped electrodes

Synchrotron

in this device, the magnetic fields are synchronized so that the particle moves in a circular rather than a spiral path

International Union for Pure and Applied Chemistry (IUPAC)

the  international body that authorizes names of new elements after their experimental discovery and confirmation

Radioactive decay

a first-order kinetic process

Radiometric dating

the method of dating objects based on their isotopes and isotope abundances

Radiocarbon dating

the technique of dating when carbon-14 is used in radiometric dating

Activity

the rate at which a sample decays and it is often expressed as number of disintegrations per unit of time

Becquerel (Bq)

the  SI unit for expressing activity

Curie (Ci )

an older unit of activity, defined as 3.7 x 10^10 disintegrations per second, which is the rate of decay of 1 g of radium

A 4.0-mCi sample of cobalt-60 undergoes

and so has an activity of  1.5 x 10^8 Bq

Nuclear Binding Energies

the energy required to separate a nucleus into its individual nucleons

Mass Defect

the mass difference between a nucleus and its constituent nucleons

Fission

Happens when heavy nuclei gain stability and therefore give off energy if they are fragmented into two midsized nuclei

Fusion

Happens when the sharp increase in the graph for small mass numbers, even greater amounts of energy are released if very light nuclei are combined, or fused together, to give more massive nuclei

Chain Reactions

reactions that multiply

Critical Mass

the amount of fissionable material large enough to maintain a chain reaction with a constant rate of fission

Supercritical Mass

a mass in excess of a critical mass

Fuel Elements

contain enriched uranium in the form of UO2 pellets encased in zirconium or stainless steel tubes

Control Rods

composed of materials that absorb neutrons, such as boron-10 or an alloy of silver, indium, and cadmium

Moderator

it functions to slow down the neutrons (to speeds of a few kilometers per second) so that they can be captured more readily by the fissionable nuclei

Primary Coolant

a substance that transports the heat generated by the nuclear chain reaction away from the reactor core

Pressurized Water Reactor

the most common commercial reactor design wherein the water acts as both the moderator and the primary coolant

Boiling Water Reactor

generates steam by boiling the primary coolant; thus, no secondary coolant is needed

Gas Cooled Reactor

uses a gas, typically CO2, as primary coolant and graphite as the moderator

Fast Breeder Reactor

offers one approach to getting more power out of existing uranium sources and potentially reducing radioactive waste

Thermonuclear Reactions

also known as Fusion Reactions

Ionizing Radiations

radiation that causes ionization which is far more harmful to biological systems than radiation that doesnt cause ionization

Nonionizing Radiations

much lower energy than ionizing radiations, such as  radiofrequency electromagnetic radiation or slow moving neutrons

Free Radical

a substance with one or more unpaired electrons, as seen in the Lewis structure shown in the margin

Gray (Gy)

the SI unit of absorbed dose, corresponds to the absorption of 1 J of energy per kilogram of tissue

Rad (Radiation Absorbed Dose)

corresponds to the absorption of 1 X 10^-2 J of energy per kilogram of tissue

RBE (Relative Biological Effectiveness)

The radiation dose is multiplies by a factor that measures the relative damages caused by the radiation

Sievert (Sv)

SI unit for effective dose