Presentation on theme: "FLASHBACK How many electrons do all atoms want in their outer shell?"— Presentation transcript:
1FLASHBACK 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.
3Chemical bonds: the attractive force that holds atoms or ions together Chemical Vocab!!Chemical bonds: the attractive force that holds atoms or ions together
4Why 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!
5Calcium ion will give up its outer electrons to both chlorine atoms bondingA bond forms when… two atoms gain, lose, or share electrons in their outer energy levels.-1-1ClClCaCl2+2CaCalcium ion will give up its outer electrons to both chlorine atoms
6Ionic bondForm between two oppositely charged ions (metal to nonmetal) one gains and one loses electrons (electron transfer)BrBr+2MgBr2MgStrong bonds form
7Ionic vs. Covalent Video covalent bondForm when atoms share one or more pairs of electrons = nonmetals to nonmetalsOxygen only needs two electrons so hydrogen shares its one valence electron so that both atoms fill their outer shells.OHH2OHIonic vs. Covalent VideoWeaker bonds form
8Electron dot Diagrams Shows only valence electrons of atom with dots around the element's symbolWhat’s the point?
10Electron dot diagrams Determine # of valence electrons Correctly place the electrons around symbolNitrogen: N Strontium: Sr Water: H2O
11FLASHBACK 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.
12Bonding Worksheet:4. Na Cl7. Be Ne11. MgCovalent or ionic bond?12. HCl_________________________14. AlO3________________________Using electron dot diagrams, draw the ionic bonds…17. NaCl
13Investigating the difference between sugar and salt! Lab time!Ionic vs. covalent...Which will win???Investigating the difference between sugar and salt!Sugar!Salt!
14Who knew Chemical Bonding could be so cool???? 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!
15Bonds Covalent Structures: make molecules and SHARE ELECTRONS Example: H20, CO2, C12H22O11same charges, so no strong attractionIonic Structures: make ionic crystals and TRANSFER ELECTRONSExample: NaCl, KI, CaF2+ and – charges make a STRONG attraction!
16IONIC StructureWhen positive and negative ions surround each other, they form tightly packed structures called ionic crystals or crystal latticesSubstances with network (ionic) structures are usually strong solids with high melting and boiling pointsSubstances made of molecules have lower melting and boiling points
17Electron dot DiagramsWhat happens if it is not the neutral element.. But the ion??e- diagram lose or gain e-? new (ion) e- diagramNaClMg
191. 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.
21FLASHBACK 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).
22Review of Terms! Cation: positively charged ion - Non metals or metals?Anion: negatively charged ion
23Chemical Formula Terms 1. Symbol: element being used2. Subscript: shows how many of the individual atoms are presentex. O2 CO HBr3. Coefficient Number: placed before the element or compound, distributed to entire compoundex. 2HBr or 2H2 + O2 2H2O4. 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)
24Chemical FormulasThe chemical symbols and numbers indicating the number of atoms contained in the basic unit of a substanceCarbon = 6 atomsC6H12O6Hydrogen = 12 atomsOxygen = 6 atomsHow many atoms of each element are present in 3 molecules of glucose?3 C6H12O6C= H= O=18
25Writing Ionic Formulas The elements overall charges have to equal zeroCompounds have no net charge!!Write the cation first with its charge, then the anion and its charge.Al+3 F-1Write the chemical formula, using subscripts to indicate how many of each ion are needed to make a neutral compound.criss-cross method: Al+3 F-1 = AlF3
26More compounds!!Balance the formula so the compound formed has a neutral chargeExamples:Ca Br –1Na S –2Al Cl-1
28Naming 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 nameName cation first (metal)Name anion (nonmetal)3. Drop the end of the anion & add suffix –ideEXAMPLE: NaCl = sodium chloride
29More naming practice cation anion Balance formula Compound name Cs+1,cesiumF-1,fluorineBa+2, bariumCl-1,chlorineAl+3, aluminumS-2, sulfurCesium FluorideCsFBarium chlorideBaCl2Aluminum sulfideAl2S3
30Naming covalent compounds Uses prefixes!!!!Number of atomsprefix1Mono-2Di-3Tri-4Tetra-5Penta-6Hexa-7Hepta-8Octa-9Nona-10Deca-If there is only one atom of the first element, it does not get a prefixEX: BF3= boron trifluorideDihydrogen monoxide = ????
32Drinking, bathing, washing, swimming… Chemistry Joke!If H20 is water, what is H204? Drinking, bathing, washing, swimming…All kinds of things!
33The 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 numberA total of 6 IONIC COMPOUND formulasAND the name of those compoundsMy IonWhat I am bonding withChemical FormulaNameFe+2O-2FeOIron Oxide
34Try these covalent molecules… Carbon monoxideCOCO2N5H8TeBr2Si3S7Carbon dioxidePentanitrogen octahydrideTellurium dibromideTrisilicon heptasulfide
35FLASHBACK1. 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 + N6. Name the following compounds:N5H SrCl2
37H O H O H Electron diagrams 1. Electron Dot Diagram: 2. Pictorial Diagrams: Hydrogen: H Oxygen: Water: H2OHOHOCovalent bonds!H
38and Chemical Reactions Chemical Changesand Chemical Reactions
39Physical ChangesOccur 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
40Chemical changesOccurs when there is a change in the arrangement of atoms so that a different substance with different properties is producedVery often,there is somekind ofevidence(for example,the formationof a gas)
41Evidence of a chemical change Formation of a gasReaction 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 tarnishingIs a neutralization reaction a chemical change?
42Evidence of chemical REACTIONs Bubbles/fizzing/formation of a gasPrecipitate formedEnergy changeColor changeOdor…
43If you're not part of the solution… You're part of the precipitate! Chemistry Joke!If you're not part of the solution…You're part of the precipitate!
44FLASHBACK1. 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 False4. Name the four evidences of a chemical rxn.5. Explain a situation in which bubbling occurs, but it is NOT a chemical change.
46Excuse me… Coke and other soft drinks are carbonated Carbonation occurs when carbon dioxide is dissolved in water or solutionThis gives the "fizz" to carbonated beveragesExcess gas needs out of the stomach.. So we burp!
47Using the materials provided: 1. 2 pieces of Alka-Seltzer Rocket Lab Time!!Using the materials provided:1. 2 pieces of Alka-Seltzer2. 1 film canister3. Water…you are tobuild a projectile!
48Use an “If-Then” statement! HypothesizingPick 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”?
49You are to write a brief lab report on your experience… - Skip lines between headings- Full sentences! Alka seltzerTitleHypothesis: (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?
50FLASHBACK EOC WORKBOOK Pg. 41 (all) An exothermic reaction __________________ heat.An endothermic reaction __________________ heat.( A + B AB ) is an example of a _____________ reaction
52Chemical Reactions and Equations: What do they mean?What do they show?
53Energy changes in reactions During any chemical reaction, there is an energy change.1. Exothermic reaction: heat is released during the reaction, gets hot!2. Endothermic reaction: heat isabsorbed during the reaction,gets cold!
54Everyday Exothermic and Endothermic Reactions The airbag's inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas. Hot blasts of the nitrogen inflate the airbag.Instant Cold PacksInstant heat packsAIRBAGS!The airbag's inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas. Hot blasts of the nitrogen inflate the airbag.
55VideosExothermic vs. EndothermicEndothermic Reaction
56Reactants Products Equation Terms A. Reactants: original substances entering a chemical rxn- what you started with, on the left sideB. Products: resulting substances- what you end with, on the right sideReactants Products
57Endothermic vs. Exothermic Calcium Chloride vs Endothermic vs. Exothermic Calcium Chloride vs. Sodium Bicarbonate… who will win the temperature war???Turn into me: Half sheet of paper
58Classifying reactions 1. Synthesis: 2 substances combine to form 1 substanceA + B -> AB2. Decomposition: 1 substance breaks down (decomposes) to 2 substancesAB -> A + B (opposite of synthesis)3. Single Displacement: 1 element replaces anotherA + BC -> AC + B4. Double Displacement: positive ion of one compound replaces positive ion of anotherAB + CD -> AD + CB
60FLASHBACK Label the following equations: (4types) Zn + HCl ZnCl2 + H22. Fe + O2 Fe2O33. SiO2 + HF SiF4 + H2O4. FeS + HCl H2S + FeCl25. In lab yesterday, what gas produced the signature “popping” sound?Single DisplacementSynthesisDouble DisplacementDouble Displacement
61Common Gas Lab! A. NaHCO3 + HCl NaCl + H20 + ______ CO2 You will be conducting reactions to produce 5 different common gases and observe their chemical and physical properties.A. NaHCO3 + HCl NaCl + H20 + ______B. Cu + 4HNO3 Cu(NO3)2 + 2H _____C. NH4Cl + NaOH NaCl + H20 + ______D. 2H2O2 2H2O + ____E. Mg + 2HCl MgCl2 + ____CO2NO2NH3O2H2
65Chemical ReactionsChemical reaction - is the process of changing reactants to products by a chemical changeChemical reactions are symbolized byReactants Products(s) solid; (l) liquid; (g) gas; (aq) aqueousare the physical states of the reactants and products
66Equations show… The reactants which enter into a reaction. The products which are formed by the reaction.The amounts of each substance used and each substance produced.___Mg(s) + __ O2(g) __ MgO(s)22
67Subscripts and coefficients We use subscripts to balance compoundsCaCl2subscripts cannot be changedWe use coefficients to balance equations2 NaCl + _ Ca(OH)2 2 NaOH + __ CaCl2
68Balancing equations!Goal: to get the same number of atoms on both sides of the equation__ Al + __ O2 ___ Al2O3__ NaCl __ Na + __ Cl2__ Li + __ H2O __ LiOH + __ H2
69What’s the point?????A balanced chemical equation represents the process of a chemical reaction in which atoms are rearranged but not created or destroyed.By balancing chemical equations, you show that mass is conserved…Law of Conservation of Mass!
70Law of Conservation of Mass Mass is neither created nor destroyed in an ordinary chemical or physical reactionMass of Reactants = Mass of Products
71LAB:Looking at the…Law of Conservation of mass!!!
72FLASHBACK Balance the following equations: ___Zn + ___HCl ___ZnCl2 + ___H22. ___Fe + ___O2 ___Fe2O33. ___SiO2 + ___HF ___SiF4 + ___H2O4. ___FeS + ___HCl ___H2S + ___FeCl25.What is the overall goal of balancing equations?
74Reactions occur when particles of reactants collide with energy Reaction Rates!Reactions occur when particles of reactants collide with energy
75Factors affecting reaction rates Temperature: higher temperature, reaction rate increasesParticles moving faster, more collision between particlesConcentration: when reactants are more concentrated, rate of reaction increasesMore particles mean more collisions
76Factors affecting reaction rates [Inhibitor: slows down a reaction] 3. Surface Area: more surface area, reaction rate increases4. Catalyst: presence of catalyst speeds up reaction without being permanently changed[Inhibitor: slows down a reaction]Video!