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Tuesday 3-19-13

Tuesday 3-19-13. WU: Draw an e-dot of any alkali metal halogen. Use the octet rule to explain why the alkali metals and the halogens are so reactive?. Li. F. Only 1 away from perfect octet (filled outer ring). Check Homework. Lewis e-dot Worksheet. Types of Chemical Compounds.

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Tuesday 3-19-13

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  1. Tuesday 3-19-13 • WU: • Draw an e-dot of any • alkali metal • halogen. • Use the octet rule to explain why the alkali metals and the halogens are so reactive?

  2. Li F Only 1 away from perfect octet (filled outer ring)

  3. Check Homework • Lewis e-dot Worksheet

  4. Types of Chemical Compounds What is the octet Rule? Atoms are not stable unless they have a full outer energy level. (Usually 8 valence electrons) So how do atoms become stable? Atoms become stable by gaining or losing electrons until they have a full outer energy level.

  5. Ionic Compounds An Ionic Bonds is an attraction between a metaland a nonmetal

  6. Is it easier for metals to gain or lose electrons to achieve an octet? Lose electrons (Then it will be left with a full energy level.)

  7. Is it easier for non-metals to gain or lose electrons to achieve an octet? O Gain electrons (they need just a few more to complete octet)

  8. Where do the electrons from metals go? • To nonmetals Where do the electrons come from to fill the nonmetals octets? • From metals

  9. Ionic Bonds Ionic Bonds occur when electrons are transferred from ametal to a nonmetal. Sodium has 1 valence electron. Chlorine needs 1 valence electron.

  10. Positive Ions Because Sodium now has 11p+ & 10e- it has more p+ Therefore Sodium has a +1 charge = Na+

  11. Negative Ions Because Chlorine now has 17p+ & 18e- it has more e- Therefore Chlorine has a -1 charge = Cl-

  12. Ionic Compounds Oppositecharges attract Since Sodium is positive and Chlorine is negative their opposite chargeshold the atoms together in anIonic Bond

  13. NaCl (Table Salt) Ionic Compounds Are weaklybonded compounds that are very easy to break apart. The only thing holding them together is their opposite charges…like two magnets. Some examples of ionic compounds include… Zinc Fluoride (ZnF2) in toothpaste

  14. Ions -formed when an atom losesor gains one or more of its valence electrons. It has two more negative electrons than positive protons. Ions have a charge because there aren’t an equal # of p+ to zero out the e- 8p+ -10e- 2e- This unique little atom would now be an oxygen ion with a chemical symbol…O-2. This is an oxygen atom… How many valence electrons? What does it need to do? What period is it in? What group is it in? Stable or unstable? By picking up two more electrons, this oxygen atom has become an ion. Negative. Because it has more negative electrons. If it gains electrons what will it’s overall charge become?

  15. Ionic Compounds Check out good old magnesium… 12p+ -10e- 2p+ How many valence electrons? Stable or unstable? What does it need to do? What group is it in? What period is it in? Magnesium has lost two negatively charged electrons. It now has more positively charged protons than electrons. 12p+ 12n0 That means it is no longer neutral. Because it has two more positive protons than electrons, the new symbol would be…Mg+2.

  16. 11p 12 n It would be a different atom, and the only way for that to happen is a nuclear reaction! Do protons ever move? NO! What would happen if a proton moved? 10 p Would that even solve the problem of too many electrons? No. It would not solve the electron problem

  17. Covalent Compounds Covalent Bonds occur between two or more nonmetals that share electrons to fill their octets.

  18. How many valence electrons does oxygen have? 6 How many electrons does it need? 2 If each oxygen shares 2 of it’s own electrons, both will have 8 v e-! O2

  19. Water (H2O) Covalent Compounds These are strongly bonded compounds and are NOT very easy to break apart. They are held together by shared electrons betweeenNONMETALS. Some examples of covalent compounds include… Ammonia NH3 Carbon Dioxide CO2

  20. Organic Compounds Organic Compounds are covalent compounds composed of mainly carbon. Some examples are fuel, alcohol, and plastic. Hydrocarbons are organic compounds that are made of only hydrogen and carbon …nothing else. Plastic is technically a hydrocarbon

  21. Final Check Up 1. What type of bond exists between any metal and any nonmetal? Ionic 2. What type of bond exists between any 2 nonmetals? Covalent 3. Which type of bond is stronger, ionic or covalent? Ionic 4. Table salt is held together by which type of bond? 5. Would it be relatively easy or difficult to break the bonds holding this molecule together?

  22. Final Check Up 6. ZnCl2is composed of a metal and nonmetal. Which type of bond holds this molecule together? Ionic Somebody mention propane? The formula for propane is C3H8. 7. Is this ionic or covalent? 8. Since propane is just carbon and hydrogen atoms, what group of molecules would it be classified as? hydrocarbon

  23. Covalent 9. What type of bond shares electrons? 10. What type of bond transfers electrons? 11. Any metal and nonmetal will form what type of bond? 12. Nonmetals bonded together form what type of bonds? Ionic Ionic Covalent

  24. How does the number of valence electrons relate to the type of bond formed between elements? Atom with few valence electrons donates its electrons to atom with lots of valence electrons. If both atoms have a lot of valence electrons than they share electrons

  25. To Do: • Update ISN

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