Nuclear Chemistry

"in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity”

Henri Becquerel Pierre Curie Marie Curie

Nobel Prize in Physics 1903

What causes radiation or nuclear decay?

The presence of too few or too many neutrons compared to protons leads to an unstable nucleus.

Reminder

N157Mass number=Protons + Neutrons

Atomic number=Protons

Radioisotopes

Radioisotopes - Isotopes that have an unstable nucleus

Nuclear Reactions and Radiation.

Nuclear Reactions: Reactions in which radioisotopes gain stability by undergoing changes.

Radiation : These changes are accompanied by the release of large amounts of energy.

Transmutation: the conversion of one chemical element or isotope into another through nuclear reaction.

Radioisotope Nuclear ReactionRadiation

Radioactive Decay

Radioactive Decay - The process where an unstable nucleus loses energy by emitting particles of radiation.

Alpha DecayConsists of a helium nuclei that has

been emitted from a radioactive source.

Symbol: Example:

42He

Th23090 Ra226

88He42

Beta Decay

A neutron is converted to a proton and an electron. The electron is emitted, the proton stays.

Particle Emitted:Symbol: Example:

e01

C146 N147 e01

Gamma Radiation

Gamma radiation is emitted often times along with alpha and beta radiation. It has no mass or electrical charge. It is high energy radiation and is very dangerous!

Particle:

Symbol:

Radioactive particles Penetrating power:

SummaryProperty Alpha

RadiationBeta Radiation

Gamma Radiation

Composition (Helium Nucleus)

Electron High energy electromagnetic radiation

Symbol γ

Charge 2+ 1- 0

Mass 4 1/1837 0

Common Source Radium-226 Carbon-14 Cobalt-60

Penetrating Power

Low Moderate Very high

Shielding Paper, clothing

Metal foil Lead, concrete

e01He42

Complete page 18 for Homework

Radioactivity and Radioactive Decay

Today’s Objective

1. Write nuclear decay equations to depict the nuclear decay of radioisotopes.

2. Predict the type of nuclear decay using the band of stability.

How do we write nuclear equations?

A nuclear equation will look like this:1. Isotope particle + element Because of the law of conservation of mass, all mass

numbers and atomic numbers, or the tops and bottoms of the complete symbols, must balance on either side of the arrow.

2. When you write your equation, balance your mass numbers followed by your atomic numbers.

CC 146

00

146

Writing Nuclear Decay EquationsNuclear Equations: Practice

 

1.

2.

3.

Word Equations4. Write the equation of lead-210 undergoing alpha decay.

5. Write the equation where lead-210 emits a beta particle.

6. Show the transmutation of uranium-237 as it undergoes alpha decay. What is the nuclide that is produced?

Homework: page 20

Transmutation• The process where a nucleus becomes a

NEW nucleus because the number of protons has been changed.

• What is the only type of radiation that does NOT change the atomic number?

Gamma (λ)- it has 0 mass and 0 charge, therefore does not affect the nucleus size!

Fission and Fusion

Show “Nuclear Power and Its Effect on the World”

http://www.youtube.com/watch?v=ur6Kb62Ci5k

Fission and Fusion

Fission Fusion

Bombard nuclei with neutronsAtom falls apartLots of energy evolvedCan create a chain reactionInstantaneousEx:Atomic Bombs, nuclear reactors

Requires input of energyTwo nuclei combine to make new atom of HeliumReleases more energy than fissionDifficult to controlEx: Sun uses fusion

Fission Reaction/ Chain Reaction

FUSION

Nuclear Power

In the News!!!!! 60 Minutes Report Fukushima Nuclear Power Plant

Japan

http://www.youtube.com/watch?v=z6cYE7PwMik