section 1: nuclear radiation under certain conditions, some nuclei can emit alpha, beta, or gamma...
TRANSCRIPT
Section 1: Nuclear Radiation
Under certain conditions, some nuclei can emit alpha, beta, or gamma radiation.
KWhat I Know
WWhat I Want to Find Out
LWhat I Learned
12(A) Describe the characteristics of alpha, beta, and gamma radiation.
3(F) Research and describe the history of chemistry and contributions of scientists.
Nuclear RadiationCopyright © McGraw-Hill Education
Essential Questions
How was radioactivity discovered and studied? What are the key properties of alpha, beta, and gamma
radiations?
Nuclear RadiationCopyright © McGraw-Hill Education
Review
nucleus
New• radioisotope• X-ray• penetrating power
Nuclear RadiationCopyright © McGraw-Hill Education
Vocabulary
The Discovery of Radiation
Nuclear chemistry is concerned with the structure of atomic nuclei and the changes they undergo.
Nuclear reactions are different from other types of reactions.
Marie Curie and her husband Pierre isolated the first radioactive materials.
Nuclear RadiationCopyright © McGraw-Hill Education
Table 1 Comparison of Chemical and Nuclear ReactionsChemical Reactions Nuclear Reactions
• Occur when bonds are broken and formed
• Involve only valence electrons• Associated with small energy changes• Atoms keep the same identity although
they might gain, lose, or share electrons, and form new substances
• Temperature, pressure, concentration, and catalysts affect reaction rates
Occur when nuclei combine, split, and emit radiation
Can involve protons, neutrons, and electrons
Associated with large energy changes Atoms of one element are often converted
into atoms of another element Temperature, pressure, and catalysts do
not normally affect reaction rates
Types of Radiation
Isotopes of atoms with unstable nuclei are called radioisotopes.
Unstable nuclei emit radiation to attain more stable atomic configurations in a process called radioactive decay.
The three most common types of radiation are alpha, beta, and gamma.
Nuclear RadiationCopyright © McGraw-Hill Education
Types of Radiation
Alpha particles have the same composition as a helium nucleus—two protons and two neutrons.
Because of the protons, alpha particles have a 2+ charge.
Alpha radiation consists of a stream of particles.
Alpha radiation is not very penetrating—a single sheet of paper will stop an alpha particle.
Nuclear RadiationCopyright © McGraw-Hill Education
Types of Radiation
Beta particles are very fast-moving electrons emitted when a neutron is converted to a proton.
Beta particles have insignificant mass and a 1– charge.
Beta radiation is a stream of fast moving particles with greater penetrating power—a thin sheet of foil will stop them.
Nuclear RadiationCopyright © McGraw-Hill Education
Types of Radiation
Gamma rays are high-energy electromagnetic radiation.
Gamma rays have no mass or charge.
Gamma rays almost always accompany alpha and beta radiation.
X rays are a form of high-energy electromagnetic radiation emitted from certain materials in an excited state.
The ability of radiation to pass through matter is called its penetrating power.
Gamma rays are highly penetrating because they have no charge and no mass.
Nuclear RadiationCopyright © McGraw-Hill Education
Nuclear RadiationCopyright © McGraw-Hill Education
Review
Essential Questions
How was radioactivity discovered and studied?
What are the key properties of alpha, beta, and gamma radiations?
Vocabulary•radioisotope•X-ray
•penetrating power