Themes:Stability and Change

Conservation of Energy and Matter

What types of isotopes are unstable?

Unstable isotopes have larger differences between number of protons and neutrons.

Look at your periodic table…what happens as the atomic # gets higher?

When a radioactive nucleus spontaneously decomposes.

In a nuclear equation both the atomic number and the mass number must be conserved.

How is that shown below??

The types of nuclear reactions we will go over are as follows.

The examples are on the powerpoint for your review, but we will do examples on the board in class: Alpha Beta Gamma Positron Emission Electron capture Nuclear bombardment

Alpha Produces

Helium Nucleus

Atomic Mass:Decrease by 4

Atomic #:Decrease by 2

Beta Produces

An electron

Atomic mass:Same

Atomic#: increase by 1

Gamma Produces

EnergyUsually accompanies another type of decay

Atomic mass and atomic number remain the same.

Positron Produces

Like a positron with a + charge

Atomic Mass:Same

Atomic #:Decrease by 1

Electron Capture

Inner electrons are captured by the nucleus.

Atomic Mass:SameAtomic number:Decrease by 1

Nuclear Bombardment

A particle is shot into the nucleus:Eg. Alpha particle or a neutron

See Example below:

Mass: Will increase

Atomic #: Will usually change

Geiger Counter—Radiation produces ionizing energy that knocks off electrons from argon. This causes an electric current which is detected.

Fiesta Ware Demonstration on youtube.http://www.youtube.com/watch?v=FKn9zJuyfWQ

Type Penetration Damaging Effects

Alpha Blocked by skin Ionizing substances in the body causing damage

Beta Penetrates 1 inch into skin, can be blocked by Aluminum foil

Least damaging

Gamma Deep penetration. Blocked by lead

Damaging because this is a very high energy form of electromagnetic radiation. Eg. Most commonly used to kill cancer cells

Positive Uses Detection on imaging machines “Killing” cells in tumors that can’t be

Negative Affects High exposure—damaging to cells (eg.

Hiroshima) Long term low exposure—

Mutation to DNA leading to cancer Mutation to DNA in eggs/sperm

Time required for half of the original same of nuclei to decay.

Carbon-14 half-life 5730 years

Uranium-238 half-life 4.5 billion years

Iodine-131 half-life 8.1 days

What type of function is this?

Use howstuffworks.com to investigate nuclear fission and fusion.

Create a Venn Diagram in your notes to compare and contrast the two processes

Case study will identify the use of isotopes in medicine.

Model will use pennies to represent radioactive decay.

Practice graphing and lab notebook skills!