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How many electrons do all atoms want in their outer shell?

FLASHBACK. How many electrons do all atoms want in their outer shell? How do these atoms get those e-’s in the outer shell? How can you tell how many valence e-’s an atom has? If atoms gain e-’s, they become ____________ charged. If atoms lose e-’s, they become ____________ charged.

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How many electrons do all atoms want in their outer shell?

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  1. FLASHBACK • How many electrons do all atoms want in their outer shell? • How do these atoms get those e-’s in the outer shell? • How can you tell how many valence e-’s an atom has? • If atoms gain e-’s, they become ____________ charged. • If atoms lose e-’s, they become ____________ charged.

  2. Chemical Reactions!! Unit 4 Ch. 20/21

  3. Chemical Vocab!! Chemical bonds: the attractive force that holds atoms or ions together

  4. Why do atoms bond? To increase stability of the atoms Group 1 and 2 metals transfer electrons to Group 16 and 17 nonmetals to create ionic bonds. Metals lose electrons & nonmetals gain electrons to achieve noble gas structure!

  5. bonding A bond forms when… two atoms gain, lose, or share electrons in their outer energy levels. -1 -1 Cl Cl CaCl2 +2 Ca Calcium ion will give up its outer electrons to both chlorine atoms

  6. Ionic bond Form between two oppositely charged ions (metal to nonmetal) one gains and one loses electrons (electron transfer) Br Br +2 MgBr2 Mg Strong bonds form

  7. covalent bond Form when atoms share one or more pairs of electrons = nonmetals to nonmetals H Oxygen only needs two electrons so hydrogen shares its one valence electron so that both atoms fill their outer shells. O H H2O Ionic vs. Covalent Video Weaker bonds form

  8. Electron dot Diagrams Shows only valence electrons of atom with dots around the element's symbol What’s the point?

  9. Electron dot diagrams P=1 H 1 e- N=0 Ca P=20 2 e- 8 e- 8 e- 2 e- N=20

  10. Electron dot diagrams • Determine # of valence electrons • Correctly place the electrons around symbol Nitrogen: N Strontium: Sr Water: H2O

  11. FLASHBACK • 1. What types of elements occupy space in groups 1 and 2? • 2. How many valence e-’s do these groups have, respectively? • 3. What will their ionic charges be, respectively, if they lose their valence e-’s? • 4. Metals will _____________ e-’s. • 5. Non-metals will ________________ e-’s. • 6. What e-’s do the bonding? • 7. Explain difference between ionic and covalent bonds.

  12. Bonding Worksheet: 4. Na 5. Cl 7. Be 10. Ne 11. Mg Covalent or ionic bond? 12. HCl_________________________ 14. AlO3________________________ Using electron dot diagrams, draw the ionic bonds… 17. NaCl

  13. Lab time! Ionic vs. covalent... Which will win??? Investigating the difference between sugar and salt! Sugar! Salt!

  14. Bonding Rap… Who knew Chemical Bonding could be so cool???? Want to give it a try??? Extra Credit by the end of the 9 weeks (March 23th) for a Chemistry Rap Video!

  15. Bonds • Covalent Structures:make molecules andSHARE ELECTRONS • Example: H20, CO2, C12H22O11 • same charges, so no strong attraction • Ionic Structures: make ionic crystals and TRANSFER ELECTRONS • Example: NaCl, KI, CaF2 • + and – charges make a STRONG attraction!

  16. IONIC Structure • When positive and negative ions surround each other, they form tightly packed structures called ionic crystals or crystal lattices • Substances with network (ionic) structures are usually strong solids with high melting and boiling points • Substances made of molecules have lower melting and boiling points

  17. Electron dot Diagrams What happens if it is not the neutral element.. But the ion?? e- diagramlose or gain e-?new (ion) e- diagram Na Cl Mg

  18. SECTION 1 REVIEW Pg. 606 # 4, 5 • CHAPTER REVIEW Pg. 626 # 4-6, 11, 14, 17, 18

  19. 1. Which of the substances has the lower melting point (which melted faster)? Was this what you expected? Why or why not? • 2. Relate your results to ionic and covalent bonding. • 3. On a molecular level, how do the bonds in sugar and salt differ? • 4. Why do atoms bond? • 5. Water (H2O) contains a(n) _________________ bond. • Calcium oxide (CaO) contains a(n) ________________ bond.

  20. FLASHBACK • EOC WORKBOOK!!! • Pg. 38 (all) • Pg. 39 (all) • Pg. 36 (all) • Pg. 37 (all)

  21. FLASHBACK • 1. Table salt (NaCl) has what kind of bond? • 2. Table sugar (sucrose, C12H22O11) has what kind of bond? • 3. When heated, what happened to the bonds in sugar? • 4. When heated, what happened to the bonds in salt? • 5. Provide the electron dot structure for Barium (Ba), Iodine (I), and Cesium (Cs).

  22. Review of Terms! Cation: positively charged ion - Non metals or metals? Anion: negatively charged ion - Non metals or metals?

  23. Chemical Formula Terms 1. Symbol: element being used 2. Subscript: shows how many of the individual atoms are present ex. O2 CO2 HBr 3. Coefficient Number: placed before the element or compound, distributed to entire compound ex. 2HBr or 2H2 + O2 2H2O 4. Oxidation Number: same as “charge”, how many electrons atoms need to gain or lose (to become stable) **get off of periodic table!! **write them on your P.T. (Al = +3)

  24. Chemical Formulas The chemical symbols and numbers indicating the number of atoms contained in the basic unit of a substance Carbon = 6 atoms C6H12O6 Hydrogen = 12 atoms Oxygen = 6 atoms How many atoms of each element are present in 3 molecules of glucose? 3 C6H12O6 C=18 H=36 O=18

  25. Writing Ionic Formulas • The elements overall charges have to equal zero • Compounds have no net charge!! • Write the cation first with its charge, then the anion and its charge. • Al+3 F-1 • Write the chemical formula, using subscriptsto indicate how many of each ion are needed to make a neutral compound. • criss-cross method: Al+3 F-1 = AlF3

  26. More compounds!! • Balance the formula so the compound formed has a neutral charge Examples: • Ca+2+ Br –1 • Na+1 + S –2 • Al +3 + Cl-1

  27. Compound Names and Formulas

  28. Naming ionic compounds • Ionic compounds are formed by the strong attractions between cations and anions. Both ions are important to the compound’s structure, so it makes sense that both ions are included in the name • Name cation first (metal) • Name anion (nonmetal) 3. Drop the end of the anion & add suffix –ide EXAMPLE: NaCl = sodium chloride

  29. More naming practice Cesium Fluoride CsF Barium chloride BaCl2 Aluminum sulfide Al2S3

  30. Naming covalent compounds • Uses prefixes!!!! If there is only one atom of the first element, it does not get a prefix EX: BF3= boron trifluoride Dihydrogen monoxide = ????

  31. Dihydrogen Monoxide!!!!!!!! Why????

  32. Chemistry Joke! If H20 is water, what is H204? Drinking, bathing, washing, swimming… All kinds of things!

  33. The name Game What’s in a name??? How many people can you “bond” with!?  You must turn in to me a piece of paper with… • Your element and it’s oxidation number • A total of 6 IONIC COMPOUND formulas • AND the name of those compounds

  34. Try these covalent molecules… Carbon monoxide • CO • CO2 • N5H8 • TeBr2 • Si3S7 Carbon dioxide Pentanitrogen octahydride Tellurium dibromide Trisilicon heptasulfide

  35. FLASHBACK 1. How many oxygen atoms are there in bleach, NaClO, AKA sodium hypochlorite? 2. Acetone (CH3COCH3), or nail polish remover, has how many total hydrogen atoms? 3. How do you determine oxidation #’s? 4. What is the oxidation # of Al, O, & Cl ? 5. Write ionic formulas: (find charges 1st then criss-cross!!) Mg + F Be + N 6. Name the following compounds: N5H8 SrCl2

  36. More naming practice • COVALENT: • NO • NO2 • N2O • IONIC: • NaF • ZnCl • CaCl2

  37. Electron diagrams H 1. Electron Dot Diagram: 2. Pictorial Diagrams: Hydrogen: H Oxygen: Water: H2O O H O Covalent bonds! H

  38. Chemical Changes and Chemical Reactions

  39. Physical Changes Occur when the size or shape of the substance is changed Occasionally, the color can change, too Regardless,the original substance(s) do not change Evidences of Physical Changes: - Bending, stretching, heat, and cooling can all cause a physical change ***All phase changes are physical changes

  40. Chemical changes Occurs when there is a change in the arrangement of atoms so that a different substance with different properties is produced Very often, there is some kind of evidence (for example, the formation of a gas)

  41. Evidence of a chemical change • Formation of a gas • Reaction with acids (like this picture of copper reacting with nitric acid) • (Sometimes) a color change can indicate a chemical change. - A good example of this is metal tarnishing Is a neutralization reaction a chemical change?

  42. Bubbles/fizzing/formation of a gas Precipitate formed Energy change Color change Odor… Evidence of chemical REACTIONs

  43. Chemistry Joke! If you're not part of the solution… You're part of the precipitate!

  44. FLASHBACK • 1. What is the main difference between a chemical and physical change? • 2. If a reaction forms a gas, you know it is a ______________ change. • 3. If something changes color, you know it’s a chemical change. True False • 4. Name the four evidences of a chemical rxn. • 5. Explain a situation in which bubbling occurs, but it is NOT a chemical change.

  45. Why do you burp after drinking a Coke?

  46. Excuse me… • Coke and other soft drinks are carbonated • Carbonation occurs when carbon dioxide is dissolved in water or solution • This gives the "fizz" to carbonated beverages • Excess gas needs out of the stomach.. So we burp!

  47. Using the materials provided: 1. 2 pieces of Alka-Seltzer 2. 1 film canister 3. Water …you are to build a projectile! Rocket Lab Time!!

  48. Hypothesizing Pick ONE question to answer and generate a hypothesis and WRITE IT DOWN… Use an “If-Then” statement! 1. How does changing the volume of water effect the time/height of rocket “launch”? 2. How does changing the amount of Alka-Seltzer effect the time/height of rocket “launch”?

  49. Lab Report You are to write a brief lab report on your experience… - Skip lines between headings - Full sentences! Alka seltzer Title Hypothesis: (your question) Data: Table? List? Conclusion: tell me what you learned (in paragraph form!) 1. What evidence did you see of a chemical reaction taking place? How does this relate to the lab? 2. Refer back to your hypothesis… was it right or wrong?? Why?? 3. What would have done differently… or how would you make this lab better?

  50. FLASHBACK • EOC WORKBOOK • Pg. 41 (all) • An exothermic reaction __________________ heat. • An endothermic reaction __________________ heat. • ( A + B  AB ) is an example of a _____________ reaction

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