Radiation
• The emission of energetic
particles
• The study of it and the
processes that produce it is
called nuclear chemistry.
• Unlike the chemistry we have
studied to this point, nuclear
chemistry often results in one
element changing into another
one.
Tragedy
• April 26, 1986, 1:24 am
• V.I. Lenin nuclear power
plant
• Chernobyl, USSR
• Explosions in reactor 4
• 31 immediate deaths, 230
hospitalizations, countless
exposures to high-level
radiation
• The aftermath continues to
this day.
Becquerel
• Discovered that his paperwrapped photographic plate
was exposed by uraniumcontaining crystals.
• This disproved his
hypothesis linking exposure
to UV light with
phosphorescence.
• But it revealed a brand-new
phenomenon that he called
the emission of uranic rays.
Marie and Pierre Curie
• Searched for the elements that produced the uranic rays
• Discovered two new emitters of uranic rays; one was a new
element (polonium)
• Radioactivity not the result of a chemical reaction
• Since the rays were not unique to uranium, a new term was
proposed: “radioactivity”
• Discovered radium as a result of its “extreme radioactivity”
Radioactivity
• The result of nuclear instability
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•
•
•
Alpha Radiation
Composed of two protons and two neutrons
Represented by the symbol for a helium nucleus
High ionizing power
Low penetrating power
Beta Radiation
•
•
•
•
An energetic electron represented by the symbol β
Smaller than alpha particles, so more penetrating
But this also means less ionizing power
In beta decay, a neutron converts to a proton, emitting an electron
and increasing the atomic number by 1.