Neutron proton ratio and stability of band graph ppt

this presentation is about nuclear chemistry, It covers neutron-proton ratio and stability band to identify an isotope is stable or radioactive.

1. NEUTRON PROTON RATIO AND STABILITY OF BAND GRAPH TOPIC

2. NEUTRON PROTON RATIO Very few nuclides exist with N/Z neutron proton ratio less than 1 (N/Z <1) means no of proton greater than no of neutron 1 H 1 and 3 He 2 (Proton rich elements are unstable except Hydrogen) For lighter stable nuclides neutron proton ratio is equal to 1 4 He 2 , 12 C 6 , 16 O 8 , 14 N 7 , 20 Ne 10 Only 85% N uclei are Stable

3. The N/Z ratio of stable nuclides gradually increases as no of proton(Z) increases. No stable nuclei exist with neutron element below Z =30 if the ratio is 1.25 appears as it is stable (4 exceptions) up to 47 if the ratio is 1.40 so it is stable (1 exception) and Z =47 to 76 if the ratio is 1.50 so it is stable (2 exceptions)

4. All nuclides with Z>83 are unstable and radioactive , Bismuth is the heaviest stable nuclide.

5. Magical Numbers Just as the noble gases the element with 2 , 4 , 8 , 10 , 16 , 18 , 20 , 36 , 40 , 54 and 86 electrons are exceptionally stable because of their filled electron shell, nuclides with N/Z valves of 2 , 4 , 8 , 10 , 16 , 18 , 20 , 36 , 40 , 54 and 86 are exceptionally stable as well.

6. These so called Magical Numbers or thought that the number of protons or neutrons in filled nucleons shells. For Example 50 Ti 22 , 88 Sr 38 Some contain double magic number 4 He 2 , 16 O 8 , 40 Ca 20 , 208 Pb 82

7. Oddness And Evenness of proton(Z) and neutron (N) valves Elements with in Even number of protons(Z) usually have large number of stable Nuclides than element with Odd number of protons(Z).

8. Number of S table N uclides For Elements 48 Through 54 Elements Atomic Numbers No of Stable Nuclides Cd 48 8 In 49 2 Sn 50 10 Sb 51 2 Te 52 8 I 53 1 Xe 54 9

9. An Even-Odd Classification of Nuclides Proton (Z) Neutron (N) No of Nuclides (STABLE) Even Even 157 Even Odd 53 Odd Even 50 Odd Odd 07

10. STABILITY BAND GRAPH Most elements have isotopes for stable isotopes an interesting plot arises when the number of neutrons is plotted versus the number of protons .

11. The plot shows only the stability or stable isotopes. This graph is often called the N uclear Belt O f Stability . The plot indicates that lighter nuclides (isotopes) are most stable when N/Z ratio is 1 .

12. Here is One more Fact Protons are positively charged and neutrons are uncharged , but holds the nucleus together. As the nucleus get bigger Electrostatic Repulsion Force between proton would break the nucleus apart. There is a Strong force exist between all nucleons.

13. This force is 100 times stronger than the Repulsion Force, but only over a short distance with in the N ucleus. Competition between the attraction of S trong Force and Repulsion Force tells us the Nuclear Stability.

14. For more understanding The Belt Of Stability will allow you to predict how unstable nuclides will decays. This typical modes of radioactive decay are Alpha decay , Beta decay and Electron capture (or Positron Emission).

15. THE END

16. THANK YOU FOR GIVING US YOUR PRECIOUS TIME Made By MUHAMMAD ARSALAN USMANI ALI RAZA SIDDIQUE SAAD UL HAQ ABDUL HAFEEZ BS CHEMISTRY 3 RD YEAR SEMESTER 6 TH