Nuclear Chemistry

" in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity ” Henri Becquerel Pierre CurieMarie 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 Mass 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. RadioisotopeNuclear ReactionRadiation

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

Alpha Decay Consists of a helium nuclei that has been emitted from a radioactive source. Symbol: Example:

Beta Decay A neutron is converted to a proton and an electron. The electron is emitted, the proton stays. Particle Emitted: Symbol: Example:

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:

Summary PropertyAlpha Radiation Beta Radiation Gamma Radiation Composition(Helium Nucleus) ElectronHigh energy electromagnetic radiation Symbolγ Charge2+1-0 Mass41/18370 Common SourceRadium-226Carbon-14Cobalt-60 Penetrating Power LowModerateVery high ShieldingPaper, clothing Metal foilLead, concrete

Complete page 18 for Homework

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. Radioactivity and Radioactive Decay

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.

Nuclear Equations (cont) Beta Decay K eCa Gamma Decay Emitted along with Alpha and Beta Radiation. Does not change the element. K eCa Change from Ar 42 = and 19 = = and 19 =

Writing Nuclear Decay Equations Nuclear Equations: Practice

Word Equations 4. 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

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! Transmutation

Fission and Fusion Show “Nuclear Power and Its Effect on the World”

Fission and Fusion FissionFusion Bombard nuclei with neutrons Atom falls apart Lots of energy evolved Can create a chain reaction Instantaneous Ex:Atomic Bombs, nuclear reactors Requires input of energy Two nuclei combine to make new atom of Helium Releases more energy than fission Difficult to control Ex: Sun uses fusion

Fission Reaction/ Chain Reaction

FUSION

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