Chapter 5: Nuclear Chemistry

radioactive

radioactive

An unstable nucleus is _____ which means that it spontaneously emits radiation to become more stable.

radiation

An unstable nucleus is radioactive, which means that it spontaneously emits small particles of energy called _______ to become more stable.

Radioisotope

An isotope of an element that emits radiation.

Atomic Symbols

Written with the mass number in the upper left corner and the atomic number in the lower left corner.

Mass Number

The sum of the numbers of protons and neutrons in the nucleus.

Atomic Number

It is equal to the number of protons.

Alpha Particle

• It has two protons and two neutrons.

• It has a mass number of 4, an atomic number of 2, and a charge of 2+.

Beta Particle

• It is a high-energy electron, has a charge of 1–, and it has a mass number of 0.

• It is formed when a neutron in an unstable nucleus changes into a proton.

Positron

• It has a positive charge with a mass number of 0.

  • It is produced by an unstable nucleus when a proton is transformed into a neutron and a positron.

Gamma Rays

These are high-energy radiation, released when an unstable nucleus undergoes a rearrangement of its particle to give a more stable, lower-energy nucleus.

Radioactive Decay

A process where a nucleus spontaneously breaks down by emitting radiation.

Alpha Decay

• An unstable nucleus may emit an alpha particle, which consists of two protons and two neutrons.

• The mass number of the radioactive nucleus decreases by 4, and its atomic number decreases by 2.

Antimatter

A particle that is the opposite of another particle — an electron.

Americium-241

Mostly found in smoke detectors used in homes and apartments, which undergoes alpha decay.

Beta Decay

• The formation of beta particle results from the breakdown of a neutron into a proton and an electron.

• The mass number of the radioactive nucleus and the mass number of the new nucleus is the same.

Radioactive Isotope Yttrium–90

A beta emitter, is used in cancer treatment and as a colloidal injection into large joints to relieve the pain of arthritis.

Positron Emission

• A proton in an unstable nucleus is converted to a neutron and a positron.

• The neutron remains in the nucleus, but the positron is emitted from the nucleus.

• The mass number of the radioactive nucleus and the mass number of the new nucleus is the same.

Gamma Emission

Pure gamma emitters are rare, although gamma radiation accompanies most alpha and beta radiation.

Transmutation

A stable nucleus is bombarded by high-speed particles such as alpha particles, protons, neutrons, and small nuclei.

activity

When a radiology laboratory obtains a radioisotope, the ____ of the sample is measured in terms of the number of nuclear disintegrations per second.

Curie (Ci)

The original unit of activity and was defined as the number of disintegrations that occurs in 1 s for 1 g of radium, which is equal to 3.7 ✕ 10^10 disintegrations/s.

Marie Curie and Pierre Curie

They discovered the radioactive elements; radium and polonium.

Becquerel (Bq)

The SI unit of radiation activity, which is 1 disintegration/s.

Radiation Absorbed Dose (Rad)

A unit that measures the amount of radiation absorbed by a gram of a material such as body tissue.

Gray (Gy)

• The SI unit for absorbed dose.

• The joules of energy absorbed by 1 kg of body tissue/

• It is equal to 100 rad.

Radiation Equivalent in Humans (Rem)

A unit that measures the biological effects of different kinds of radiation.

Sievert (Sv)

• The SI unit for the equivalent dose or biological damage.

Half-Life

The amount of time it takes for one-half of a sample to decay.

Decay Curve

A diagram of the decay of a radioactive isotope.

Phosphorous

A radioisotope used in the treatment of leukemia has a half-life of 14.3 days.

Radiological dating

A technique used by geologists, archaeologists, and historians to determine the age of ancient objects.

Carbon Dating (Carbon-14)

The method for determining the age of an object containing organic material is by using the properties of radiocarbon, a radioactive isotope of carbon.

Scanner

• An apparatus used to produce an image of the organ.

• The gamma rays emitted from the radioisotope in the organ can be used to expose a photographic plate, producing a scan of the organ.

Radioactive iodine uptake

The standard method of determining thyroid function.

Positron emission tomography (PET)

An imaging method where Positron emitters with short half-lives such as carbon-11, oxygen-15, nitrogen-13, and fluorine-18 are used.

Positron-Emitting Isotopes

These are used to study brain function, metabolism, and blood flow.

Computed Tomography (CT) Scan

• Another imaging method is used to scan organs such as the brain, lungs, and heart.

• A computer monitors the absorption of 30 000 X-ray beams directed at successive layers of the target organ.

• This technique is successful in the identification of hemorrhages, tumors, and atrophy.

Magnetic resonance imaging (MRI)

• A powerful imaging technique that does not involve X-ray radiation.

• It is based on the absorption of energy when the protons in hydrogen atoms are excited by a strong magnetic field.

Brachytherapy

• Also known as seed implantation.

• It is an internal form of radiation therapy.

• With internal radiation, a high dose of radiation is delivered to a cancerous area, while normal tissue sustains minimal damage.

Atomic Energy

The energy generated by splitting the atom.

Chain Reaction

A fission reaction that will continue once it has been initiated by a high-energy neutron bombarding a heavy nucleus such as uranium-235.

Nuclear Fission

The bombardment of a large nucleus breaks it apart into smaller nuclei, releasing one or more types of radiation and a great amount of energy.

Nuclear Fusion

Small nuclei combine to form larger nuclei while great amounts of energy are released.

Au-198

Used for Liver imaging; treatment of abdominal carcinoma

Ce-141

Used for Gastrointestinal tract diagnosis; measuring blood flow to the heart

Cs-131

Used for Prostate brachytherapy

F-18

Used for Positron emission tomography (PET)

Ga-67

Used for Abdominal imaging; tumor detection

Ga-68

Used for the Detection of pancreatic cancer

I-123

Treatment of thyroid, brain, and prostate cancer

I-131

Treatment of Graves’ disease, goiIr-192ter, hyperthyroidism, thyroid and prostate cancer

Ir-192

Treatment of breast and prostate cancer

P-32

Treatment of leukemia, excess red blood cells, pancreatic cancer

Pd-103

Used for Prostate brachytherapy

Sr-85

Detection of bone lesions; brain scans

Tc-99m

Imaging of skeleton and heart muscle, brain, liver, heart, lungs, bone, spleen, kidney, and thyroid; most widely used radioisotope in nuclear medicine

Y-90

Treatment of liver cancer