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Nuclear Chemistry. CHAPTER 10. Intro Clip (2:40). 10.1 Radioactivity. Radioactivity - when an unstable atomic nucleus emits charged particles and energy. Nuclear decay - atoms of 1 element can change into atoms of a different element.

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Nuclear chemistry

Nuclear Chemistry

CHAPTER 10

Intro Clip (2:40)


10 1 radioactivity
10.1 Radioactivity

  • Radioactivity - when an unstable atomic nucleus emits charged particles and energy.

  • Nuclear decay - atoms of 1 element can change into atoms of a different element.


Over100 mammoths died at a sinkhole in hot springs south dakota
Over100 mammoths died at a sinkhole in Hot Springs, South Dakota.

  • Can you determine a way to calculate how old these once furry elephants might be?


Carbon 14 dating
Carbon-14 Dating Dakota.

They are about 26,000 years old.

Mammoth Tooth

FYI: Ms. Lolich went here on a quick trip west.

Yes…….she is a science geek.


Nuclear radiation
Nuclear radiation Dakota.

  • Charged particles & energy that are emitted from the nuclei of radioisotopes.

    • Alpha

    • Beta

    • Gamma


Alpha decay
Alpha Decay Dakota.

  • positively charged (+2)

  • 2 protons and 2 neutrons (like He but no e)

  • symbol 42He or the Greek letter α.

  • Low penetrating power

  • Travel only a few cm. thru air.

  • Does not pose a health hazard


What do those numbers mean
What do those numbers mean? Dakota.

Mass Number

Atomic Number


Example of alpha decay
Example of Alpha Decay Dakota.

24094 Pu 23692 U + 42 He



Beta decay
Beta Decay Dakota.

  • Occurs when a neutron decomposes into a proton and an electron.

  • negative charge

  • no mass

  • symbol 0−1e or the Greek letter β.

  • 100x more penetrating than the α particle.

  • Can pass through clothing and damage skin.

  • * assigned an atomic number of −1


Example of beta decay
Example of Beta Decay Dakota.

22888 Ra 22889 Ac + 0-1e


Ask ms lolich for her weird way to remember this1

B “ Dakota.e”TA DECAY

Ask Ms. Lolich for her Weird way to remember this……


Gamma decay
Gamma Decay Dakota.

  • Energetic form of light similar to X-ray

  • Has no mass - does not affect atomic # or mass # (like an electron)

  • Often occurs with α and β radiation

  • no charge

  • Greek symbol is γ

  • Can travel through tissue and solid material - stopped by concrete and lead.


Example of gamma decay
Example of Gamma Decay Dakota.

24094 Pu 24094 Pu + γ radiation




Effects of nuclear radiation
Effects of Nuclear Radiation Dakota.

Background radiation - naturally occurs in the environment.

1. You’re exposed daily.

2. Found in: air, water, rocks, plants, and animals, comic rays.

3. Not harmful.


Effects of nuclear radiation1
Effects of Nuclear Radiation Dakota.

Once nuclear radiation exceeds background levels, it can damage the cells and tissues of your body.

David Hahn needs Proactive – NOT!


Detecting nuclear radiation
Detecting Nuclear Radiation Dakota.

  • Devices that are used to detect nuclear radiation include:

    • Geiger counters

    • Film badges.


10 2 rates of nuclear decay
10.2 Rates of Nuclear Decay Dakota.

  • A half-life is the time required for one half of a sample of a radioisotope to decay.

Video Clip (1:24)


So how long does it take anyhow
So how long does it take anyhow? Dakota.

  • Half-lives can vary

    • fractions of a second

    • billions of years.

  • Nuclear decay rates are constant.



After one half life 8 07 days half of a sample of iodine 131 will have decayed into xenon 131
After one half-life (8.07 days), half of a sample of iodine-131 will have decayed into xenon-131.




Half lives of various radioisotopes
Half-lives of various Radioisotopes sample will have decayed.


Lab to follow
Lab to follow sample will have decayed.

  • Calculating Half-Life of BariumStudents will observe radioactive decay and collect data from their Geiger counter to graph the half-life decay process.


10 3 artificial transmutation
10.3 Artificial Transmutation sample will have decayed.

  • Transmutation - conversion of atoms of 1 element to atoms of another.

  • Involves a nuclear change, NOT a chemical change.

Video Clip (2:04)


Who s your daddy daughter
Who’s your daddy daughter? sample will have decayed.


Natural all the way
Natural all the way sample will have decayed.

  • In natural transmutations, the nucleus decays spontaneously.

  • There is only 1 reactant (or the nucleus) that undergoes the transformation.

  • Alpha or beta particles are emitted.


So how do they do it artificially
So how do they do it artificially? sample will have decayed.

  • Scientists bombard the atomic nuclei with high-energy particles such as protons, neutrons, or alpha particles.

  • Particles are accelerated in accelerators, by using electric and magnetic fields.


Way to go ernie
Way to go Ernie!! sample will have decayed.

  • In 1919, Ernest Rutherford bombarded nitrogen-14 with α particles.

  • Notice the left side balanced with right.


You try determine x
You try….determine “X”? sample will have decayed.

4

He

2


One more time determine x
One more time….Determine “X”? sample will have decayed.

30

P

15


10 4 fission and fusion
10.4 Fission and Fusion sample will have decayed.

  • P4.12d

  • Identify the source of energy in fission and fusion nuclear reactions.

Video Clip (FIRST 1:06 )


So what is nuclear force
So what is sample will have decayed.nuclear force?

  • Binds protons and neutrons together in the nucleus.

  • Over very short distances its greater than the electric forces.

Remember + and + repel but NOT with nuclear force!!


Fission
Fission sample will have decayed.

  • The splitting of an atomic nucleus into two smaller parts.

  • Tremendous amounts of energy are produced from very small amounts of mass.

  • This is how our nuclear reactor plants work.


Did you know
Did you know? sample will have decayed.

  • 1 kilogram of uranium-235 is equal to the chemical energy produced by burning more than 17,000 kilograms of coal!


Nuclear fission of uranium 235
Nuclear Fission of Uranium-235 sample will have decayed.


Nuclear fission of uranium 2351
Nuclear Fission of Uranium-235 sample will have decayed.


Nuclear fission of uranium 2352
Nuclear Fission of Uranium-235 sample will have decayed.


Nuclear fission of uranium 2353
Nuclear Fission of Uranium-235 sample will have decayed.


Real live action shots of fission
Real live “action” shots of Fission sample will have decayed.


What ms lolich sees in her head
What Ms. Lolich sees in her head sample will have decayed.

FISSION

ISSIO

SCISSORS

ISSO

So Fission is like Scissors – right?


Fusion
Fusion sample will have decayed.

  • When the nuclei of 2 atoms

    combine to form a larger nucleus.

  • Fusion also has a small fraction of the reactant mass that is converted into energy.

  • This is how our sun works and reactor made in Junkyard Science article.


What do you need you ask
What do you need you ask? sample will have decayed.

  • High temperatures.

  • Plasma must exist.

  • Plasma is a state of matter in which atoms have been stripped of their electrons.

    Think of plasma (gas) = nuclei & electrons


Let s break it down
Let’s break it down…. sample will have decayed.

…More like “stick it” together.


Something to consider as we end our chapter
Something to consider as we end our chapter. sample will have decayed.

Video Clip (3:26)


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