Chapter 30- Nuclear Reactions

What is the nucleus?

It is the central part of the atom. It consists of neutrons and protons. These two particles are called nuclei. Neutrons are not charged and have slightly more mass than protons. Protons are postively charged.

 

What is a nuclear reaction?

This is a reaction that affects the nucleus of an atom. Chemical changes do not affect the nucleus; therefore, they cannot cause nuclear reactions.

What is Radioactivity?

Radioactivity is the natural decay of a nuclei. There are three kinds of decay:
  • Alpha Decay: a Helium nucleus- 2 protons & 2 neutrons=> +2 charge
  • Beta Decay: an electron=> -1 charge
  • Gamma Radiation: pure electro-magnetic energy...a very high energy photon.

    •  Note: A common term used for this change in the nuclei is called, transmutation.

     

    There are two important terms to remember for radioactive decay

  • Half-Life (T½ ): the time it takes for half the material to decay.
  • Decay Constant (Lambda): The number of decays/sec per atom.

    •  The relationship is:

      

                               Lambda = .693/T½

Practice problems: See Worksheet 1

    Two important kinds of nuclear reactions

  • Fission- The splitting of heavy nuclei into smaller ones. This is the reaction that we use in today's generation of nuclear power plants.
  • Fusion-The combining of light nuclei into heavier ones. This is the reaction that takes palce naturally in the Sun and other stars. Hopefully, mankind will soon harness this energy for peaceful energy production.

    • Nuclear Equations:

    The important thing to remember in balancing a nuclear equation is that the mass numbers and the atomic numbers must balance on both sides of the equation. The actual atomic mass units (a.m.u.) do not balance...thus the energy is evolved.

     (See Worksheet 2 & 3)

  • How much energy evolves?
    •                            1 a.m.u. = 931 Mev

    What are subatomic particles?

    They are the particles that makeup electrons, protons, and neutrons. Most subatomic particles have been discovered using Linear Accelerators like Stanford's SLAC and Circular Accelerators like FermiLab

    The proton's and neutron's building blocks are called quarks and the electron's family of particles are called leptons.

     

      More great information about Nuclear Energy:

      These Questions will be asked on the test!

       

    1. How many Nuclear Plants are there in the U.S.? Answer...
    2. Where is the first high-yield permanent storage facility being built? Answer...
    3. The economics of nuclear power. How many billions of dollars have U.S. consumers saved according to a USCEA 1993 report from 1973-93? Answer...
    Copyright - © 1996- H.G. Repasky