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