1. Antoine Henri Becquerel
Discovery of Radioactivity
U salts cloud film on protected plates
Ionized air
Could be deflected by B field (unlike X rays)
Discovered radioactive decay
Antoine Henri Becquerel
Parent Nucleus
(Before)
Daughter Nucleus
(After)
Radiation

2. Types of decay and radiation
Effect on Parent
A - 4, Z - 2
A - 0, Z + 1 (Conservation of charge)
(neutron to proton)
A - 0, Z - 1
(proton to neutron)
A - 0, Z - 0
Parent loses mass
Decay Type
 (Alpha)
- (Beta-)
+ (Beta+)
 (Gamma)
What it is
2p2n (He nuc)
(4 cm air)
e- (electron)
(Thin Al foil, 1-3 m air)
e+ (positron)
High energy Photon
( nm)
(some thickness of lead)

4. 21082Pb ______ +   = 2p2n, 4 nucleons, 2 protons 210 - 4 = 206
= 80 Hg (Mercury)
206/80 Hg

5. 4019K ______ + - - = Neutron turns to proton
Nucleons remain unchanged
Z = = 20 Ca
40/20 Ca

6. 158O ______ + + + = Proton turns to a neutron
Nucleons remain unchanged
Z = = 7 (Nitrogen)
15/7 N

8. 14561Pm ______ +   = 2p2n, 4 nucleons, 2 protons 145 - 4 = 141
= 59 Pr (Praseodymium)
141/59 Praseodymium

9. 6027Co ______ + - - = Neutron turns to proton
Nucleons remain unchanged
Z = = 28 Ni
60/28 Ni

10. 4019K ______ + + + = Proton turns to a neutron
Nucleons remain unchanged
Z = = 18 Ar
40/18 Ar

11. 22286Rn ______ +   = High energy photon Nucleons remain unchanged
Protons remain unchanged
222/86 Rn