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Explore the fundamentals of nuclear chemistry, from nuclear reactors and bombs to isotopes and radioactive decay. Discover key figures like Marie Curie and understand concepts such as half-life and nuclear stability. Unravel the mysteries behind alpha, beta, and gamma decay, and learn how to calculate remaining nuclei in radioactive samples. With engaging visuals and clear explanations, this resource is ideal for students and enthusiasts alike.
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Intro to NuclearChemistry MYP Honors Chemistry http://www.chem.orst.edu/graduate/pics/Reactor.jpg
How does a nuclear reactor work? http://www.lanl.gov/science/1663/images/reactor.jpg
How does a small mass contained in this bomb cause…… • Nuclear Bomb of 1945 known as “fat man” http://www.travisairmuseum.org/assets/images/fatman.jpg
…this huge nuclear explosion? http://library.thinkquest.org/06aug/01200/Graphics/705px-Nuclear_fireball.jpg
Is there radon in your basement? http://a.abcnews.com/images/Blotter/abc_1radon_ad_070625_ssh.jpg
Nucleons • Protons and Neutrons
Isotopes • Atoms of a given element with: same #protons but different # neutrons
H H H http://education.jlab.org/glossary/isotope.html
Radioactive Isotopes • Isotopes of certain unstable elements that spontaneously emit particles and energy from the nucleus. • Henri Beckerel 1896 accidentally observed radioactivity of uranium salts that were fogging photographic film. • His associates were Marie and Pierre Curie.
Marie Curie: born 1867, in Poland as Maria Sklodowska • Lived in France • 1898 discovered the elements polonium and radium. http://www.radiochemistry.org/nuclearmedicine/pioneers/images/mariecurie.jpg
Marie Curie a Pioneer of Radioactivity • Winner of 1903 Nobel Prize for Physics with Henri Becquerel and her husband, Pierre Curie. • Winner of the sole 1911 Nobel Prize for Chemistry.
3 Main Types of Radioactive Decay • Alpha a • Betab • Gamma g
Alpha Decay Emission of alphaparticlesa : • helium nuclei • two protons and two neutrons • charge +2e • can travel a few inches through air • can be stopped by a sheet of paper, clothing.
Alpha Decay Uranium Thorium
Alpha Decay http://education.jlab.org/glossary/alphadecay.gif
Beta Decay • Beta particles b: electrons ejected from the nucleus when neutrons decay ( n -> p+ +b- ) • Beta particles have the same charge and mass as "normal" electrons.
Beta Decay • Beta particles b: electrons ejected from the nucleus when neutrons decay n -> p+ +b- • Beta particles have the same charge and mass as "normal" electrons. • Can be stopped by aluminum foil or a block of wood.
Beta Decay Thorium Protactinium
Gamma Decay • Gamma radiation g : electromagnetic energy that is released. • Gamma rays are electromagnetic waves. • They have no mass. • Gamma radiation has no charge. • Most Penetrating, can be stopped by 1m thick concrete or a several cm thick sheet of lead.
Examples of RadioactiveDecay Alpha Decay Po Pb + He Beta Decay p n + e n p + e C N + e Gamma Decay Ni Ni + g (excited nucleus)
Part II Nuclear Stability Half-Life
Nuclear Stability • Depends on the neutron to proton ratio.
Band of Stability Number of Neutrons, (N) Number of Protons (Z)
What happens to an unstable nucleus? • They will undergo decay • The type of decay depends on the reason for the instability
What type of decay will happen if the nucleus contains too many neutrons? • Beta Decay
Example: 14 14 0 C N + e In N-14 the ratio of neutrons to protons is 1:1 6 -1 7
Radioactive Half-Life (t1/2 ): • The time for half of the radioactive nuclei in a given sample to undergo decay.
Common Radioactive Isotopes Isotope Half-Life Radiation Emitted Carbon-14 5,730 years b, g Radon-222 3.8 days a Uranium-235 7.0 x 108 years a, g Uranium-238 4.46 x 109 years a
Radioactive Half-Life • After one half life there is 1/2 of original sample left. • After two half-lives, there will be 1/2 of the 1/2 = 1/4 the original sample.
Graph of Amount of RemainingNuclei vs Time A=Aoe-lt A
Example You have 100 g of radioactive C-14. The half-life of C-14 is 5730 years. • How many grams are left after one half-life? Answer:50 g • How many grams are left after two half-lives?
Problem A sample of 3x107 Radon atoms are trapped in a basement that is sealed. The half-life of Radon is 3.83 days. How many radon atoms are left after 31 days? answer:1.2x105 atoms