Structure Of Atoms Part 3

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Structure Of Atoms Part 3

  1. 1. A t o m i c S t r u c t u r e Part 3
  2. 2. Recap
  3. 3. Recap <ul><li>Isotopes : </li></ul><ul><li>Atoms of the same element having the same number of protons but different number of neutrons </li></ul><ul><li>Hydrogen has three isotopes and chlorine has two isotopes </li></ul>
  4. 4. Recap <ul><li>The attractive force between the positive charge on the nucleus and the negative charge on the electrons is called electrostatic force </li></ul><ul><li>The way the electrons are arranged is called its electronic structure </li></ul>
  5. 5. Recap 2 nd shell 8 electrons 4 th shell 8 electrons Nucleus 3 rd shell 8 electrons (proton number 20) 1 st shell 2 electrons
  6. 6. Recap <ul><li>To find the electronic configuration of an atom, we should </li></ul><ul><li>Fill the electrons into the shell nearest to the nucleus first. This shell can take a maximum of 2 electrons </li></ul><ul><li>(2) Once this shell is filled, the electrons go to the next available shell which has a maximum capacity of 8 electrons, and so on. </li></ul>
  7. 7. Overview of topic Structure of Atoms Isotopes Electronic Arrangement Electronic Structure and the Periodic Table Ions Atomic Structure
  8. 8. Today’s Menu <ul><li>Outermost electrons </li></ul><ul><li>Electronic structures and The Periodic Table </li></ul><ul><li>Electrons Structures of Noble Gases </li></ul><ul><li>Ions </li></ul><ul><li>- Positively charged (+) ions </li></ul><ul><li>- Negatively charged (-) ions </li></ul>
  9. 9. What are outermost electrons
  10. 10. What are outermost electrons Na <ul><li>The shell furthest away from nucleus is known as the outermost shell </li></ul><ul><li>The electrons on the outermost shell are known as the outermost electrons </li></ul><ul><li>Outermost electrons are also known as valence electrons </li></ul>
  11. 11. What are outermost electrons Na <ul><li>The outermost electrons take part in chemical reactions </li></ul><ul><li>The inner-shell electrons do not take part in chemical reaction </li></ul>
  12. 12. What are outermost electrons Example 4 6 3 4 6 3 2, 6 2, 4 2, 8, 3 Electronic Configuration Oxygen Carbon Aluminium No. of e - taking part in chemical reactions No. of outermost e - (Valency) Element
  13. 13. Electronic Structures & The Periodic Table
  14. 14. Electronic Structures & The Periodic Table <ul><li>The Periodic Table is a way of arranging elements by their valency </li></ul><ul><li>Elements with the same number of outermost electrons are in the same Group </li></ul><ul><li>The vertical set of elements in the Periodic Table is called a Group </li></ul>
  15. 16. Electronic Structures & The Periodic Table 2, 8, 5 P 5 2, 5 N V 2, 8, 4 Si 4 2, 4 C IV 2, 8, 3 Al 3 2 ,3 B III 2, 8, 2 Mg 2 2, 2 Be II 2, 8, 1 Na 1 2,1 Li I Valency Electronic Configuration Example Group
  16. 17. Electronic Structures & The Periodic Table 2, 8, 7 Cl 7 2, 7 F VII 2, 8, 6 S 6 6 O VI Valency Electronic Configuration Example Group
  17. 18. Electron Structure of Noble Gases
  18. 19. Electron Structure of Noble Gases <ul><li>Noble gases are in Group 0 </li></ul><ul><li>They have full outermost shell </li></ul>Electronic Configuration: 2 (duplet) Electronic Configuration: 2, 8 (octet) Electronic Configuration: 2, 8, 8 (octet) Examples: He Ne Ar
  19. 20. Electron Structure of Noble Gases <ul><li>Noble gases are unreactive = inert gases </li></ul><ul><li>Noble gases are very stable as they have no tendency to combine with other elements </li></ul>
  20. 22. Practice Time
  21. 23. Ions
  22. 24. Ions <ul><li>Atoms form ions by losing or gaining electrons to achieve the stable full shell configuration of a noble gas </li></ul><ul><li>Ion is a charged particle </li></ul>
  23. 25. Ions <ul><li>There are 2 types of ion: </li></ul>Ions Positively (+) charged ions (Cations) Negatively (-) charged ions (Anions)
  24. 26. Ions <ul><li>Remember this. . . </li></ul><ul><li>In an Atom, </li></ul><ul><li>No. of = No. of </li></ul><ul><li>Therefore, an atom is </li></ul>protons electrons electrically neutral
  25. 27. Positively Charged Ion <ul><li>When electrons are lost from an atom, the atom has more protons than electrons </li></ul><ul><li>There is an overall positive charge </li></ul><ul><li>Hence, a positively charged ion (cation) is formed </li></ul>X – e - X +
  26. 28. Negatively Charged Ion <ul><li>When electrons are gained from an atom, the atom has less protons than electrons </li></ul><ul><li>There is an overall negative charge </li></ul><ul><li>Hence, a negatively charged ion (anion) is formed </li></ul>X + e - X -
  27. 29. Why do atoms lose or gain electrons
  28. 30. Why do atoms lose or gain electrons Atoms lose or gain electrons so as to achieve the stable full shell configuration of a noble gas i.e. duplet (2 e - in the outermost shell) or octet (8 e - in the outermost shell)
  29. 31. Practice Time
  30. 32. Summary
  31. 33. Summary <ul><li>Electrons found on the outermost shells are known as the outermost electron (Valence electrons) </li></ul><ul><li>2) The outermost electrons take part in chemical reactions </li></ul>
  32. 34. Summary <ul><li>The Periodic Table is a way of arranging elements by their valency </li></ul><ul><li>Elements with the same number of outermost electrons are in the same Group </li></ul>
  33. 35. Summary <ul><li>Noble gases are in Group 0 </li></ul><ul><li>They have full outermost shell </li></ul>Electronic Configuration: 2 (duplet) Electronic Configuration: 2, 8 (octet) Electronic Configuration: 2, 8, 8 (octet) Examples: He Ne Ar
  34. 36. Summary <ul><li>Atoms form ions by losing or gaining electrons to achieve the stable full shell configuration of a noble gas </li></ul><ul><li>There are 2 types of ion: </li></ul>Ions Positively (+) charged ions (Cations) Negatively (-) charged ions (Anions)
  35. 37. Summary <ul><li>Positively charged ion (cation) </li></ul><ul><li>Negatively charged ion (anion) </li></ul>X – e - X + X + e - X -
  36. 38. Summary <ul><li>Atoms lose or gain electrons so as to achieve the stable full shell configuration of a noble gas </li></ul><ul><li>i.e. duplet (2 e- in the outermost shell) or octet (8 e- in the outermost shell) </li></ul>
  37. 39. Any Questions

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