Atomic Theory, Isotopes and Radioactive Decay Section 7.1

What is (Define) Radioactivity Radiation Isotopes Decay

Radioactivity Matter that is changing, within the nuclei of its atoms Deals with non-normal matter, something that behaves irregularly. Matter that can give off something and cause radio interference (Electromagnetic). Imagine 100 years ago driving through the mountains and your radio doesn’t work properly, or buying a souvenir and putting it on your T.V and it messes up the image on the screen Matter that is changing, within the nuclei of its atoms

Radiation Is what is given off (emit) and causes the interference. They are the high-energy, short wave particles and rays of energy.

Isotopes Any element, same # of protons, with a different # of neutrons and overall mass. Stability ≈ Decay (excess neutrons): neutron  proton

Types of Decay Normal Radioactive To decay by emitting radiation. Implies to breakdown, fall apart and become smaller. Something is changing form (composition). Decay is a process. To decay by emitting radiation. High-energy, short wavelength particles & rays Normal decay is like mold, rust, erosion

The 3 Main Types of Radiation found in the Decay Process What are (Define): The 3 Main Types of Radiation found in the Decay Process

Alpha An Alpha particle is the nucleus of a Helium atom. It has 2 protons and 2 neutrons.

Beta Beta particle is an electron Caused from a neutron decay

Gamma A gamma particle is a high-energy, short wavelength ray (like light). Caused from changes in energy (between levels or states)

Radiation Types (Penetration) Think of Alpha (α), Beta (β) and Gamma (γ) as letters A, B, C that equal changes according to size. A = Biggest = α B = Next = β C = Smallest = γ

Radiation Types (Repulsion) Think of Alpha (α), Beta (β) and Gamma (γ) in terms of charges (attract and repel). α = Positive (+2) β = Negative (-1) γ = No Charge

Radiation Types

2 Rules for Writing Nuclear Equations 1. The sum of the mass numbers on each side of the equation does not change (stays the same) Don’t Forget to Balance!!!! 2 Rules for Writing Nuclear Equations 2. The sum of the atomic charges (in the nucleus) on each side of the equation does not change (stays the same)

Isotope Tables

Radioactive decay & Nuclear Equations Show what happens when Plutonium 242 decays by alpha emission. Show what happens when Uranium 238 decays by alpha emission. 3. Show what happens when Carbon 15 decays by beta emission. 4. Show what happens when Hydrogen 3 decays by beta