1 nuclear chemistry active chemistry. 2 review atomic notation
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Nuclear ChemistryActive Chemistry
Review Atomic Notation
NucleonsProtons and NeutronsThe nucleons are bound together by the strong force.Nucleons are made of Quarks which are considered to be fundamental particles.
Quarks bind together with gluons to make composite particles called hadrons. The most common examples of a hadron are neutrons and protons.
IsotopesAtoms of a given element with: same #protons but different # neutrons
Isotopes of Carbon
Radioactive IsotopesIsotopes 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: 1876-1934 born in PolandLived in France1898 discovered the elements polonium and radium.She discovered radioactivity, the spontaneous disintegration of some elements into smaller pieces.Winner of 1903 Nobel Prize for Physics with Henri Becquerel and her husband, Pierre Curie.Winner of the sole 1911 Nobel Prize for Chemistry.She died of aplastic anaemia, a blood disease that often results from exposure to large amounts of radiation.
Nuclear Reactions vs. Normal Chemical ChangesNuclear reactions involve the nucleusThe nucleus opens, and protons and neutrons are rearrangedThe opening of the nucleus releases a tremendous amount of energy that holds the nucleus together called binding energyNormal Chemical Reactions involve electrons, not protons and neutrons
Types of Radiation Alpha (a) a positively charged (+2) helium isotope we usually ignore the charge because it involves electrons, not protons and neutronsBeta () an electronGamma () pure energy; called a ray rather than a particle
Other Nuclear Particles Neutron Positron a positive electronProton usually referred to as hydrogen-1Any other elemental isotope
Sheilding Ability ChemSaver p. 20
Atomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutronsAZ11100-10+142ChemSaver p. 20
Balancing Nuclear EquationsConserve mass number (A). The sum of protons plus neutrons in the products must equal the sum of protons plus neutrons in the reactants.235 + 1 = 138 + 96 + 2x1Conserve atomic number (Z) or nuclear charge. The sum of nuclear charges in the products must equal the sum of nuclear charges in the reactants.92 + 0 = 55 + 37 + 2x023.1
Emission of alpha particles a :
helium nuclei two protons and two neutrons charge +2 can travel a few inches through aircan be stopped by a sheet of paper, clothing.
Alpha DecayUranium Thorium
Beta DecayBeta 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 DecayThorium Protactinium
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.
Transmutation, or artificial radioactivity, is when you hit a nucleus with a projectile. If the projectile hits the nucleus at a great enough rate, the projectile and the nucleus will fuse together and make a larger nucleus. In most cases, the nucleus will eject a by-product particle.
The target nucleus is the isotope which is bombarded (in the example above, the lead-207)The projectile is the particle fired at the nucleus (carbon-12)The product is the new nucleus produced by the reaction (francium-218) The ejected particle is the light nucleus or particle emitted in the reaction (hydrogen-1)
Example: What is the product nucleus when a uranium-235 nucleus is hit with a hydrogen-2 nucleus, and a neutron is ejected from the target?
By the law of conservation of matter, the product side of the reaction should add up to the reactant side in terms of the atomic number.
Learning CheckWhat radioactive isotope is produced in the following bombardment of boron?10B + 4He ? + 1n 5 2 0
Learning CheckWhat radioactive isotope is produced in the following bombardment of boron?10B + 4He 13N + 1n 5 2 7 0
Write Nuclear Equations!Write the nuclear equation for the beta emitter Co-60.60Co0e+60Ni 27 -128
Nuclear FissionFission is the splitting of atomsThese are usually very large, so that they are not as stableChemSaver p. 20
Representation of a fission process.
Nuclear Fission & POWERCurrently about 103 nuclear power plants in the U.S. and about 435 worldwide.17% of the worlds energy comes from nuclear.
Figure 19.6: Diagram of a nuclear power plant.
Nuclear FusionFusion nuclei combine to form a more massive nucleus
2H + 3H 4He + 1n + 1 1 2 0
Occurs in the sun and other stars
EnergyChemSaver p. 20