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13.1 Properties of nucleus 13.2 Binding energy and mass defect.

is defined as the central core of an atom that is positively charged and contains protons and neutrons. UNIT 26 : NUCLEUS. (2 HOURS). 13.1 Properties of nucleus 13.2 Binding energy and mass defect. 26.1 Properties of nucleus (1/2 Hour).

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13.1 Properties of nucleus 13.2 Binding energy and mass defect.

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  1. is defined as the central core of an atom that is positively charged and contains protons and neutrons. UNIT 26 : NUCLEUS (2 HOURS) 13.1 Properties of nucleus 13.2 Binding energy and mass defect.

  2. 26.1Properties of nucleus (1/2 Hour) At the end of this topic, students should be able to: • State the properties of proton and neutron • Define • Proton number • Nucleon number • Isotopes • Use to represent a nuclide

  3. 26.1 Properties of nucleus • A nucleus of an atom is made up of protons and • neutronsthat is also known asnucleons. ~10-15 m A nucleus

  4. 13.1 Properties of nucleus Properties of proton and neutron. 1.672 x 10-27 1.675 x 10-27

  5. Proton number • defined as the number of protons in the nucleus. • also called as atomic number, Z. • Nucleon number • defined as the total number of neutrons and • protons in the nucleus. • also called as atomicmass number, A. • Isotopes • defined as the atoms of the same element whose nuclei contain the same number of protons (Z) but different number of neutrons (N). hidrogen tritium deuterium

  6. The atomic nucleus can be represented as where X = symbol for the element Z = atomic number (number of protons) A = atomic mass number = total number of protons and neutrons Example : Iron-56 26 protons 56 – 26 = 30 neutrons A - Z = N

  7. Example 26.1 Complete the table below:

  8. 26.2Binding energy and mass defect (1 1/2 Hours) At the end of this topic, students should be able to: • Define and determine mass defect • Define and determine binding energy, • Identify the average value of binding energy per nucleon of stable nuclei from the graph of binding energy per nucleon against nucleon number.

  9. 26.2 Binding energy and mass defect Binding energy,E • defined as the energy required to separate a nucleus into its individual protons and neutrons without providing them with kinetic energy. • An alternate interpretation of the binding energy is the energy released (emitted) when the nucleus is formed from its individual nucleons.

  10. p p p n n n p n + 28.30 MeV n n p p n n p p To separate a nucleus energy is required 28.30 MeV + To form a nucleus energy is released 26.2 Binding energy and mass defect

  11. 26.2 Binding energy and mass defect Mass defect Δm • defined as the difference between the sum of • the masses of individual nucleons that form • an atomic nucleus and the mass of the • nucleus.

  12. binding energy mass defect 26.2 Binding energy and mass defect • The relationship between the binding energy • and mass defectis given by in joule speed of light • In nuclear physics, mass is measured in unified • atomic mass unit (u).

  13. 26.2 Binding energy and mass defect

  14. 26.2 Binding energy and mass defect • The mean (average) binding energy of a nucleus is • callled binding energy per nucleon.

  15. Example 26.2 a) Calculate the binding energy of the deuterium. Given

  16. or

  17. b) The binding energy of the neon is 160.647 MeV. Find its atomic mass. Given 19.992 u

  18. Example 26.3 Calculate the average binding energy per nucleon of the iron-56 . Given

  19. or E = 8.81 MeV/nucleon

  20. Exercise Determine the total binding energy and the binding energy per nucleon for the nitrogen -14 nucleus . Given 104.6 MeV,7.47 MeV/nucleon

  21. Binding energy per nucleon as a function of mass number,A Greatest stability Binding energy per nucleon (MeV/nucleon) Mass number A

  22. The binding energy per nucleon is a measure of • stability of the nucleus. • The greater the binding energy per nucleon, the • more stablethe nucleus is. From the graph: • For light nuclei, the value of EB/A rises rapidly • from 1 MeV/nucleon to 8 MeV/nucleon with • increasing mass number A. • For the nuclei with A between 50 and 80, the • value of EB/A ranges between 8.0 and 8.9 • Mev/nucleon. The nuclei in these range are • very stable. • The nuclide has the largest binding • energy per nucleon (8.7945 MeV/nucleon).

  23. For nuclei with A > 62, the values of EB/A • decreases slowly, indicating that the nucleons • are on average, less tightly bound. • For heavy nuclei with A between 200 to 240, • the binding energy is between 7.5 and 8.0 • MeV/nucleon.These nuclei are unstable and • radioactive. Hidrogen with one proton has no binding energy per nucleon.

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