Periodic table

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chemistry ppt 2

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Periodic table

  1. 1. PERIODIC TABLE Chemistry Part 2
  2. 2. Chemistry <ul><li>A knowledge of chemistry is essential for understanding the structure and function of animals because body functions involve chemical reactions. </li></ul>
  3. 3. Matter <ul><li>Matter – is anything that occupies space and has mass. </li></ul>
  4. 4. Elements <ul><li>Elements – Pure substances that cannot be broken down into simpler units. </li></ul>
  5. 5. Atoms <ul><li>Atoms –are composed of a nucleus and an electron cloud. </li></ul><ul><li>Nucleus – central core of an atom and is made up of Protons (particle with a positive charge) and Neutron – (particle without a charge, it’s neutral) </li></ul>
  6. 6. Atoms <ul><li>Electron cloud – electrons around the nucleus </li></ul><ul><li>Electrons – particle with a negative charge </li></ul>
  7. 7. Periodic Table <ul><ul><li>Atomic number = number of protons </li></ul></ul><ul><ul><li>Atomic Mass= </li></ul></ul><ul><li>Total numbers </li></ul><ul><li>Of protons plus </li></ul><ul><li>Neutrons in </li></ul><ul><li>Nucleus. </li></ul>
  8. 8. Isotopes <ul><li>Same atoms; different numbers of neutrons, therefore different atomic mass. </li></ul><ul><li>Examples: Carbon 12 and Carbon 14 </li></ul><ul><li>Carbon Atomic Number 6, so how many neutrons in Carbon 12? </li></ul><ul><li>6 </li></ul><ul><li>Carbon 14? </li></ul><ul><li>8 </li></ul>
  9. 9. Radioisotopes <ul><li>Unstable Isotopes </li></ul><ul><li>Unstable nuclei, which tend to undergo radioactive decay. </li></ul><ul><li>Carbon 14 is unstable isotope. (half-life of 5,730 years) </li></ul><ul><li>Carbon 12 is stable. </li></ul>
  10. 10. Electrons <ul><li>Energy levels – different locations of electrons around the nucleus </li></ul><ul><li>First level – 2 electrons </li></ul><ul><li>Second & all other levels – 8 electrons </li></ul>
  11. 11. Electrons <ul><li>The amount of electrons in the outermost energy level leads to properties of the atom – will it react with other atoms? </li></ul>
  12. 12. Valence Electrons <ul><li>Number of electrons in outermost shell. </li></ul><ul><li>If the outer shell is full then NO REACTION! </li></ul><ul><li>Column 8, valence shell has 8 electrons, it is full, NO REACTION!! </li></ul><ul><li>Columns 1-7? </li></ul><ul><li>Fill in info on periodic table. </li></ul>
  13. 14. Electron Dot Diagram <ul><li>Illustrates energy levels and the number of electrons in all shells. </li></ul><ul><li>Can put symbol in center to represent nucleus. </li></ul><ul><li>Easy way to determine number of valence electrons. </li></ul>
  14. 16. Lewis Dot Structure <ul><li>Write symbol for element. </li></ul><ul><li>Indicate valence electrons by putting dots representing electrons found in OUTER SHELL ONLY. (only show electrons that are available for bonding) </li></ul><ul><li>Ex: </li></ul>
  15. 17. uc
  16. 18. Covalent Bonds <ul><li>Atoms SHARE electrons. </li></ul><ul><li>Use Lewis Dot Structures </li></ul>
  17. 19. Ionic Bonds <ul><li>Electrons TRANSFER of electrons. </li></ul><ul><li>Use Lewis Dot Structure </li></ul>

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