Nuclear Chemistry A Short Study
Mar 27, 2015
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
1. 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
2. Non-Ionizing Radiation – radiation that does not have enough energy to ionize matter
3. Ionizing Radiation – High-energy radiation which is capable of knocking electrons out of atoms
4. Nuclear Radiation – radiation produced from the nucleus of an atom
5. 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 Decay1. Alpha Emission
– Helium Nucleus is given off
2. 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 PowerUses fission to generate electricity
Fission = The splitting of a large nucleus to produce smaller ones and energyBombardment with neutronsNeed critical mass that will sustain a chain
reactionControlled in a reactorUncontrolled 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 in1. Nuclear Reactors2. Nuclear Explosions3. Accelerators
• Transuranium – synthetic elements with an atomic number greater than 92