1. Lesson Objectives 1. Recap Atomic Structure NEW 2. Isotopes

2. Lesson Objectives 1. Recap Atomic Structure NEW 2. Isotopes

3. Recap on Atomic Structure Structure of atom B. Relative masses and charges of proton, neutron and electron C. Chemical symbols D. Electronic configuration

4. Recap on Atomic Structure Structure of atom B. Relative masses and charges of proton, neutron and electron C. Chemical symbols D. Electronic configuration

5. The Atomic Structure

6. What is an Atom? Atoms are the smallest particle of an element.

8. The Story of Atoms Atoms have positive charges concentrated in their small nucleus! There are neutrons! Ernest Rutherford (1871 -1937) Democritus 460 BC Sir James Chadwick (1891 -1974) Joseph John Thompson (1856-1940) Niels Bohr (1885-1962) ATOMA PLUM PUDDING MODEL 1898

9. Bohr’s Atom electrons in orbits nucleus http://www.chem.iastate.edu/group/Greenbowe/sections/projectfolder/flashfiles/atom.swf

10. Structure of Atom An atom consists mostly of empty space. A positively charged nucleus, densely concentrated in the centre. The nucleus contains protons and neutrons, which are tightly packed. Negatively charged electrons move around the nucleus in fixed orbits or paths. 10

11. Recap on Atomic Structure Structure of atom B. Relative masses and charges of proton, neutron and electron C. Chemical symbols D. Electronic configuration

12. Recap on Atomic Structure Structure of atom B. Relative masses and charges of proton, neutron and electron C. Chemical symbols D. Electronic configuration

14. It is electrically neutral

16. Recap on Atomic Structure Structure of atom B. Relative masses and charges of proton, neutron and electron C. Chemical symbols D. Electronic configuration

17. Interpreting Chemical Symbol O 16 Mass=P+N mass number (nucleon number) mass number is the total number of protons and neutrons in an atom. Number of neutrons in the oxygen atom is: 16 – 8 = 8. chemical symbol 8 proton number (atomic number) atomic number (proton number) is the number of protons in an atom. Each oxygen atom has 8 protons. As the number of electrons is equal to the number of protons in an atom, each oxygen atom contains 8 electrons. P=E No. of protons= no. of electrons 16

18. Recap on Atomic Structure Structure of atom B. Relative masses and charges of proton, neutron and electron C. Chemical symbols D. Electronic configuration

19. Recap on Atomic Structure Structure of atom B. Relative masses and charges of proton, neutron and electron C. Chemical symbols D. Electronic configuration

20. The Electronic Configuration of Atoms Mass number (Nucleon) O 16 O 8 Atomic number (Proton)

21. The Electronic Configuration of Atoms Mg

22. Summary for Atomic Structure (I) The structure of an atom The relative charges & relative masses of proton, neutron & electron Defined mass number & atomic number Learnt how to interpret chemical symbols The electronic configuration of atoms

23. Lesson Objectives 1. Recap Atomic Structure NEW 2. Isotopes

24. Today… Isotopes

25. Isotopes 1. Definition of Isotopes 2. Uses of Isotopes

26. Isotopes 1. Definition of Isotopes 2. Uses of Isotopes

27. Activity Find your fellow group members! (1min)

28. Definition of Isotopes Isotopes are atoms of the same element which contains the same number of protons but different number of neutrons. Same P different n

29. Isotopes mass number O O 17 O 18 16 proton number 8 8 8 Oxygen-17 Oxygen-18 Oxygen-16 n = 8 n = 17 – 8 = 9 n = 18 – 8 = 10

30. Isotopes Isotopes have the same chemical properties but slightly different physical properties

31. Q. Do all Isotopes of the same element have the same mass?

32. Isotopes 1. Definition of Isotopes 2. Uses of Isotopes

33. Pair Work

34. Uses of Radioactive Isotopes Food irradiation Archaeological dating (carbon-dating) Smoke detectors Radioactive tracers

35. Summary Recap on Atomic Structure 1. Definition of Isotopes 2. Uses of Isotopes

36. Definition of Isotopes Isotopes are atoms of the same element which contains the same number of protons but different number of neutrons. Same P different n

37. Quiz http://chemistry.about.com/library/weekly/blionquiz.htm