Drill – 10/25

1. Write the nuclear equation for the alpha decay of Pu-239

2. Write the nuclear equation for the electron capture of Argon-37.

Test on Thursday – 10/28From Chapter 3:

– Atomic number, Average Atomic Mass, Mass #– Protons, neutrons, electrons– Ions & Isotopes– Calculating average atomic mass– Atomic Structure History (know famous

scientists/experiments/atomic models)– Mole, Molar mass, & Avogadro’s number– Converting between moles, mass, & particles

From Chapter 21:– Balancing nuclear reactions– Types of radioactive decay (alpha, beta, gamma, positron,

electron capture)– Why radioactive decay occurs– Half-life – Fusion & Fission

Nuclear Fission and Fusion

Radiation Composition

& Symbol

Is shielded or stopped by?

Alpha

Beta

Gamma

Shielding Radiation

, aluminum

• Alpha & beta do not cause internal harm to humans

• Gamma radiation harms living cells. It is used to clean medical equipment and irradiation of bacteria from foods.

• Gamma radiation can break DNA strands and cause mutations (ex. in the gene to suppress tumor production and the gene to repair DNA), causing cancer.

• Gamma radiation can also treat cancer by killing cancer cells. The radiation is directed at cancer cells and kills them first because they are replicating the fastest.

Nuclear Fission• A heavy nucleus splits into more stable

nuclei of intermediate mass.

A-bombs• Atomic bombs are an

example of Fission Reactions.

• “Little boy” and “Fat man” were Atomic bombs made from fission reactions with uranium and plutonium respectively.

• A fission chain reaction is started and continues until the bomb destroys itself.

Nuclear Power Plants

map: Nuclear Energy Institute

Nuclear Power Plants• Uranium-235 undergoes nuclear fission

and releases thermal (heat) energy. • This turns water to steam which spins

turbines.• The turbines produce electrical energy.

• Nuclear waste is fuel rods with unreacted uranium and radioactive products of fission. Right now this waste is buried in waste management facilities, like Yucca Mountain.

Nuclear Fusion• Low-mass nuclei combine to form a

heavier, more stable nucleus.

Requires high temperatures and/or pressure and often a fission reaction to get the initial particles.

Hydrogen Bombs

• Hydrogen bombs are an example of nuclear fusion.

• Two isotopes of hydrogen, 2H and 3H, fuse together to produce a lot of energy in the process.

• H-bombs release significantly more energy than atomic bombs.

The Sun: Nuclear Fusion

Sun

+ +

Fourhydrogen

nuclei(protons)

Two betaparticles

(electrons)

Oneheliumnucleus

He e2 H4 4

2

0

1-

1

1 + Energy

Nuclear Fission Nuclear Fusion

Nuclear Fission Nuclear Fusion

A heavy atom splits into two or more lighter nuclei

Ex: Atomic Bombs & Nuclear reactors

High temp and pressure are used to combine light atoms to make heavier atoms

Ex: Fuels the sun and stars & Hydrogen Bombs

Release huge

amounts of energy

Produce nuclear waste