Ppt nuclear strability

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1. Nuclear Stability

2. What is the nuclear stability?

3. Nuclear stability means that nucleus is stable meaning that it does not spontaneously emit any kind of radioactivity (radiation).

4. Nuclear Stability Graph The nucleus holds the neutrons and protons by the forces which counter balances each other. In the diagram shown below, the red line depicts the stable nuclei and green line depicts the nuclei with the equal number of neutron and protons.

5. if the nucleus is unstable (not stable), it has the tendency of emitting some kind of radiation, i.e., it is radioactive. Radioactive

6. Stable nucleus – non-radioactive Unstable nucleus – radioactive Keep in mind that less stable means more radioactive and more stable means less radioactive.

7. We want to know why there is a radioactivity. What makes the nucleus a stable one?

8. There are no concrete theories to explain this, but there are only general observations based on the available stable isotopes.

9. How do we predict the nuclear stability?

10. One of the simplest ways of predicting the nuclear stability is based on nucleus contains odd/even number of protons and neutrons:

11. Protons Neutrons Stability Odd Odd least stable Nuclides containing odd numbers of both protons and neutrons are the least stable means more radioactive.

12. Protons Neutrons Odd Even Nuclides contain odd numbers of protons and even numbers of neutrons are less stable than nuclides containing even numbers of protons and odd numbers of neutrons.

13. Protons Neutrons Stability Even Even most stable Nuclides containing even numbers of both protons and neutrons are most stable means less radioactive.

14. In general, nuclear stability is greater for nuclides containing even numbers of protons and neutrons or both.

15. Examples to solve:

16. Based on the even-odd rule , predict which one would you expect to be radioactive in each pair?

17. Solve it; (a) 16 8 O and 17 8 O

18. Solve it ; ( b) 35 17 Cl and 36 17 Cl

19. Answer for (b) ; ( b) The 35 17 Cl has 17 protons and 18 neutrons (odd-even) and the 36 17 Cl has 17 protons and 19 neutrons (odd-odd). Hence, 36 17 Cl is radioactive.

20. Solve it ; ( c) 20 10 Ne and 17 10 Ne

21. Answer for (c) ; (c) The 20 10 Ne contains 10 protons and 10 neutrons (even-even) and the 17 10 Ne contains 10 protons and 7 neutrons (even-odd). Therefore, 17 10 Ne is radioactive.

22. Solve it ; (d) 4020Ca and 4520Ca

23. Answer for (d) ; (d) The 4020Ca has even-even situation and 4520Ca has even-odd situation. Thus, 4520Ca is radioactive.