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Radioactivity and types of Radiation
Contents:•Discovery of Radiation•Types of Decay/Radiation
•Whiteboard
Discovery of Radioactivity
TOC
Antoine Henri Becquerel 1852-1908
Studying phosphorescence of U saltsSalts cloud film on protected platesIonized airCould be deflected by B field (unlike X rays)
Discovered radioactive decay (demo radioactive rocks)
Parent Nucleus(Before)
Daughter Nucleus(After)
Radiation
•Mass + energy•Charge•Number of nucleons
Conservation Laws - things which are neither created nor destroyed
Types of decay and radiation
TOC
Decay Type
(Alpha)
- (Beta-)
+ (Beta+)
(Gamma)
What it is
2p2n (He nucleus)
e- (electron)
e+ (Positron)
High energy Photon (Small )
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 - 0Parent loses mass
Whiteboards: Decay Products
1 | 2 | 3 | 4 | 5
TOC
W
21082Pb ______ +
206/80 Hg
= 2p2n, 4 nucleons, 2 protons210 - 4 = 20682 - 2 = 80 Hg (Mercury)
W
= 2p2n, 4 nucleons, 2 protons145 - 4 = 14161 - 2 = 59 Pr (Praseodymium)
14561Pm ______ +
141/59 Praseodymium
W
158O ______ + +
15/7 N
+ = Proton turns to a neutronNucleons remain unchangedZ = 8 - 1 = 7 (Nitrogen)
W
4019K ______ + +
40/18 Ar
+ = Proton turns to a neutronNucleons remain unchangedZ = 19 - 1 = 18 Ar
W
4019K ______ + -
40/20 Ca
- = Neutron turns to protonNucleons remain unchangedZ = 19 + 1 = 20 Ca
W
6027Co ______ + -
60/28 Ni
- = Neutron turns to protonNucleons remain unchangedZ = 27 + 1 = 28 Ni
W
22286Rn ______ +
222/86 Rn
= High energy photonNucleons remain unchangedProtons remain unchanged
Decay series:U238>Th234+Th234>Pa234+Pa234>U234+U234>Th230+Th230>Ra226+Ra226>Rn222+Rn222>Po218+•Uh - then it gets a little complicated•Eventually the product is stable•Online Nuclides
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