Our Radioactive World Do you know some of the uses of radiation?

Much of the radiation in our world is naturally ocurring and useful Much of the radiation in our world is naturally ocurring and useful. This is the electromagnetic spectrum. Note that it includes gamma rays which we will encounter in our study of nuclear chemistry.

RADIATION Non-Ionizing Ionizing Visible Light Microwaves Infrared TV – Radio Waves Radar Waves High Energy UV Radioactive Atoms Gamma Rays Neutrons X-Rays Some radiation has enough energy to knock electrons from atoms. This is called ionizing radiation. The ions created may cause damage to human tissue. The ions created are reactive and want to bond with something.

We will also look at particles that can be emitted during nuclear reactions. Do not worry about the spherical versus deformed nucleus distinction.

General Terms Note that Parent and daughter are general names used to describe the species involved in nuclear reactions.

Alpha Radiation Alpha Radiation Large nuclei may be unstable. Spit out an alpha particle. Note the symbol for alpha.

Parent This just shows the nucleus of a plutonium atom. For nuclear reactions, we are not concerned with the valence electrons, like with chemical reactions.

Daughter When Pu undergoes alpha decay, U-235 is the daughter nuclide produced along with the alpha particle that got ejected from Pu’s nucleus.

Alpha Decay Equation You will be expected to be able to write these equations which keep track of the species involved. Note that atomic numbers on the right add up to the atomic number on the left as do the mass numbers.

Beta Radiation A neutron is converted into a proton and an electron. Electron is ejected. Note the symbol for a beta particle. Notice that it is simply an electron. The lower right –hand diagram shows that in the nucleus a neutron splits into a proton and an electron during beta decay.

Parent Note the mass number and atomic number are properly represented here.

Daughter Beta decay of carbon-14 produces nitrogen-14.

Beat Decay Equation Note that the beta particle has a negative charge.

Gamma Decay Nucleus is more stable. The release of energy brings the nucleus to a lower energy and thus is more stable. Cobalt-60 is used to irradiate food. The high energy released kills bacteria on the surface of food.

232U 232U +γ Gamma Decay Equation Note that there is no change in mass number, nor atomic number.

Try to fill this out before revealing the answers.

Penetration Ability I can’t read Japanese, but the picture is great.

Penetrating Ability Simpler picture but not as cool as the Japanese one.

Alpha Particle a Characteristics • +2 charge • 2 protons • 2 neutrons • Large mass Range • Very short range • 1" -2" in air Shielding • Paper • Outer layer of skin Hazards • Internal Sources • Plutonium • Uranium • Radium • Thorium • Americium a a a a a

Beta Particle b Characteristics • -1 charge • Small mass Range • Short range • About 10' in air Shielding • Plastic safety glasses • Thin metal Hazards • Skin and eyes • Can be internal Sources • Radioisotopes • Activation Products • Sealed sources

Gamma Ray g Characteristics • No charge • No mass • Similar to x-rays Range • Long range • About 1100' in air Shielding • Lead • Steel • Concrete Hazards • External (whole body) • Can be internal Sources • X-ray machines • Electron microscopes • Sealed sources • Accelerators • Nuclear reactors • Radioisotopes Paper Plastic Lead