1. Nuclear Decay

2. Nuclear Symbols Mass number, A (p+ + no) Element symbol
Atomic number, Z
(number of p+)

3. Balancing Nuclear Equations
Areactants = Aproducts
= (1)
= (0)
Zreactants = Zproducts

4. Balancing Nuclear Equations #2
222
226 = 4 + ____
222 Rn 86
88 = 2 + ___ 86
Atomic number 86 is radon, Rn

5. Balancing Nuclear Equations #395
= (1) + ____ 95 Y 39 39
= (0) + ____
Atomic number 39 is yttrium, Y

6. Alpha Decay Alpha production (a): an alpha particle is a
helium nucleus
Alpha decay is limited to heavy, radioactive
nuclei

7. Alpha Radiation
Limited to VERY large nucleii.

8. Beta Decay Beta production (b): A beta particle is an
electron ejected from
the nucleus
Beta emission converts a neutron to a proton

9. Beta Radiation
Converts a neutron into a proton.

10. Gamma Ray Production Gamma ray production (g):
Gamma rays are high energy photons produced in association with other forms of decay.
Gamma rays are massless and do not, by themselves, change the nucleus

11. Gamma Ray Production Gamma ray production (g):
Gamma rays are high energy photons produced in association with other forms of decay.
Gamma rays are massless and do not, by themselves, change the nucleus

12. Positron Production Positron emission:
Positrons are the anti-particle of the electron
Positron emission converts a proton to a neutron

13. Electron Capture
Electron capture: (inner-orbital electron is captured by the nucleus)
Electron capture converts a proton to a neutron

14. Types of Radiation

15. Nuclear Stability
Decay will occur in such a way as to return a nucleus to the band (line) of stability.
The most stable nuclide is Iron-56
If Z > 83, the nuclide is radioactive
Graphic – Wikimedia user : Napy1kenobi

16. A Decay Series
A radioactive nucleus reaches a stable state by a series of steps
Graphic – Wikimedia Commons User Tosaka

17. Half-life
Graphic -

18. Decay Kinetics
Decay occurs by first order kinetics (the rate of decay is proportional to the number of nuclides present)
N0 = number of nuclides
present initially
N = number of nuclides
remaining at time t
k = rate constant
t = elapsed time

19. Calculating Half-life
t1/2 = Half-life (units dependent on rate constant, k)

20. Sample Half-Lives