Chapter 25: Nuclear Chemistry:

Isotope particles with same number of protons but different number of neutrons particles with same atomic number (Z), but different mass number

Henri Becquerel ruined some photographic plates with x-rays from a uranium source and radioactive decay was discovered in 1896.

Radioactivity One of the pieces of evidence for the fact that atoms are made of smaller particles came from the work of Marie Curie (1876-1934). She discovered radioactivity, the spontaneous disintegration of some elements into smaller pieces.

Nuclear Reactions Equations for reactants & products balance total mass # balance total charge

Spontaneous Radioactive Stability Production of an  particle Production of a  particle Production of  rays Spontaneous Fission

1. production of a particle

2. production of b particle

3. production of g rays

4. Spontaneous Fission

II. Nuclear Fission

Nuclear Fission Sub-Critical Critical Supercritical

then radioactive decomposition: ½ life = 1.3 sec

then radioactive decomposition: ½ life = 1.3 sec

then radioactive decomposition: ½ life 18.3 months

then radioactive decomposition: ½ life 18.3 months

Other Types of Nuclear Reactions Positron: a positive electron 207 K-capture: the capture of an electron from the first or K shell An electron and proton combine to form a neutron.

III. Nuclear Fusion Example #1 Requires 40,000,000 K to overcome electrostatic repulsion

How on earth??? Hydrogen bombs

How on earth??? Circular laser array