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 paper-

wrapped photographic plate was exposed by uranium-containing 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

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.