Nuclear Chemistry A Short Study

A Review Element – Chemical substance that cannot be divided by chemical means All atoms of the same element have the same atomic number Atom – A small piece of matter made of a nucleus and electron cloud(s) Nucleus contains protons and neutrons Neutral atoms have equal numbers of protons and electrons

Review Continued Atomic Number – the number of protons in the nucleus. Mass Number – The total number of protons and neutrons in the nucleus Ion – an atom that has lost or gained electrons Isotopes – atoms of the same element that have different numbers of neutrons

The New Stuff Radiation – energy that is emitted from a source and travels through space Measured with a Geiger Counter Have You Ever Been Exposed to Radiation? Is all radiation harmful?

More Terms Non-Ionizing Radiation – radiation that does not have enough energy to ionize matter Ionizing Radiation – High-energy radiation which is capable of knocking electrons out of atoms Nuclear Radiation – radiation produced from the nucleus of an atom Radioactive – unstable nucleus which spontaneously emits ionizing radiation

Types of Nuclear Radiation Alpha Particle – (α) helium ions that have no electrons and are positively charged Beta Particle – (β) electrons emitted at very high speed Gamma Ray – (γ) high energy radiation which has no mass or charge Positron – same mass as an electron but with a positive charge

Gamma Ray

Nuclear Decay Spontaneous Starts as a parent Becomes a daughter Gives off heat (energy) May continue as a series until a stable atom is formed Mass Number and electric charge must be conserved during a nuclear change

Band of Stability

Types of Decay Alpha Emission Beta Emission Helium Nucleus is given off Beta Emission Electron (β-) or Positron (β+) is given off

Decay Terms Half-life – the time it takes for one-half of the parent to decay Will the material ever be gone? What do we do with it? Some Examples of half-life Radioactive dating?

Fission

Nuclear Power Uses fission to generate electricity Fission = The splitting of a large nucleus to produce smaller ones and energy Bombardment with neutrons Need critical mass that will sustain a chain reaction Controlled in a reactor Uncontrolled in an explosion Fusion = The combining of small nuclei to form larger ones releasing energy

Fission Reactor

Fusion Reactor

Synthetic Elements Transmutation – changing one element into another Carried out in Nuclear Reactors Nuclear Explosions Accelerators Transuranium – synthetic elements with an atomic number greater than 92