Presentation on theme: "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."— Presentation transcript:
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. FLASHBACK
Unit 4 Ch. 20/21
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!
CaCl 2 Calcium ion will give up its outer electrons to both chlorine atoms Ca Cl +2
Mg Br +2 MgBr 2
H O H Oxygen only needs two electrons so hydrogen shares its one valence electron so that both atoms fill their outer shells. Weaker bonds form H2OH2O Ionic vs. Covalent Video
Shows only valence electrons of atom with dots around the element's symbol Whats the point?
P=1 N=0 1 e- H P=20 N=20 Ca 2 e-8 e- 2 e-
Nitrogen: N Strontium: Sr Water: H 2 O
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. FLASHBACK
Bonding Worksheet: 4. Na5. Cl 7. Be10. Ne 11. Mg Covalent or ionic bond? 12. HCl_________________________ 14. AlO 3 ________________________ Using electron dot diagrams, draw the ionic bonds… 17. NaCl
Ionic vs. covalent... Which will win??? Investigating the difference between sugar and salt! Salt! Sugar!
Who knew Chemical Bonding could be so cool???? Want to give it a try??? Extra Credit by the end of the 9 weeks (March 23 th ) for a Chemistry Rap Video!
Covalent Structures: make molecules and SHARE ELECTRONSSHARE ELECTRONS Example: H 2 0, CO 2, C 12 H 22 O 11 same charges, so no strong attraction Ionic Structures: make ionic crystals and TRANSFER ELECTRONSTRANSFER ELECTRONS Example: NaCl, KI, CaF 2 + and – charges make a STRONG attraction!
A.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
What happens if it is not the neutral element.. But the ion?? e- diagramlose or gain e-? new (ion) e- diagram Na Cl Mg
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.
1. Table salt (NaCl) has what kind of bond? 2. Table sugar (sucrose, C 12 H 22 O 11 ) 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). FLASHBACK
Review of Terms! 1.Cation: positively charged ion - Non metals or metals? 2.Anion: negatively charged ion - Non metals or metals?
1. Symbol: element being used 2. Subscript: shows how many of the individual atoms are present ex. O 2 CO 2 HBr 3. Coefficient Number: placed before the element or compound, distributed to entire compound ex. 2HBror 2H 2 + O 2 2H 2 O 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)
The chemical symbols and numbers indicating the number of atoms contained in the basic unit of a substance C 6 H 12 O 6 Carbon = 6 atoms Hydrogen = 12 atoms Oxygen = 6 atoms How many atoms of each element are present in 3 molecules of glucose? C=18 H=36 O=18 3 C 6 H 12 O 6
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 subscripts to indicate how many of each ion are needed to make a neutral compound. criss-cross method : Al +3 F -1 = AlF 3
Balance the formula so the compound formed has a neutral charge Examples: Ca +2 + Br –1 Na +1 + S –2 Al +3 + Cl -1
Ionic compounds are formed by the strong attractions between cations and anions. Both ions are important to the compounds structure, so it makes sense that both ions are included in the name 1.Name cation first (metal) 2.Name anion (nonmetal) 3. Drop the end of the anion & add suffix –ide EXAMPLE: NaCl = sodium chloride
cationanion Balance formula Compound name Cs +1,cesiumF -1,fluorine Ba +2, bariumCl -1,chlorine Al +3, aluminumS -2, sulfur Aluminum sulfide Cesium Fluoride Barium chloride CsF BaCl 2 Al 2 S 3
Uses prefixes!!!! Number of atoms prefix 1Mono- 2Di- 3Tri- 4Tetra- 5Penta- 6Hexa- 7Hepta- 8Octa- 9Nona- 10Deca- If there is only one atom of the first element, it does not get a prefix EX: BF 3 = boron trifluoride Dihydrogen monoxide = ????
If H 2 0 is water, what is H ? Drinking, bathing, washing, swimming … All kinds of things!
Whats in a name??? How many people can you bond with!? You must turn in to me a piece of paper with… 1.Your element and its oxidation number 2.A total of 6 IONIC COMPOUND formulas 3.AND the name of those compounds My Ion What I am bonding with Chemical Formula Name Fe +2 O -2 FeOIron Oxide
Try these covalent molecules… CO CO 2 N 5 H 8 TeBr 2 Si 3 S 7 Carbon monoxide Carbon dioxide Pentanitrogen octahydride Tellurium dibromide Trisilicon heptasulfide
1. How many oxygen atoms are there in bleach, NaClO, AKA sodium hypochlorite? 2. Acetone (CH 3 COCH 3 ), 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 1 st then criss-cross!!) Mg + F Be + N 6. Name the following compounds: N 5 H 8 SrCl 2 FLASHBACK
COVALENT: NO NO 2 N 2 O IONIC: NaF ZnCl CaCl 2
1. Electron Dot Diagram:2. Pictorial Diagrams: Hydrogen: H Oxygen: Water: H 2 O H O O H H Covalent bonds!
Chemical Changes and Chemical Reactions
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
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)
1.Formation of a gas 2.Reaction with acids (like this picture of copper reacting with nitric acid) 3.(Sometimes) a color change can indicate a chemical change. - A good example of this is metal tarnishing Is a neutralization reaction a chemical change?
1.Bubbles/fizzing/formation of a gas 2.Precipitate formed 3.Energy change 4.Color change 5.Odor…
Chemistry Joke! If you're not part of the solution … You're part of the precipitate!
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 its 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. FLASHBACK
Why do you burp after drinking a Coke?
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! Excuse me…
Using the materials provided: 1. 2 pieces of Alka-Seltzer 2. 1 film canister 3. Water …you are to build a projectile!
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?
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?
EOC WORKBOOK Pg. 41 (all) A.An exothermic reaction __________________ heat. B.An endothermic reaction __________________ heat. C.( A + B AB ) is an example of a _____________ reaction FLASHBACK
Chemical Reactions and Equations: What do they mean? What do they show?
During any chemical reaction, there is an energy change. 1. Exothermic reaction: heat is released during the reaction, gets hot! 2. Endothermic reaction: heat is absorbed during the reaction, gets cold!
Everyday Exothermic and Endothermic Reactions Instant Cold Packs Instant heat packs The airbag's inflation system reacts sodium azide (NaN 3 ) with potassium nitrate (KNO 3 ) to produce nitrogen gas. Hot blasts of the nitrogen inflate the airbag. AIRBAGS! 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.
Exothermic vs. Endothermic Endothermic Reaction
A. Reactants: original substances entering a chemical rxn - what you started with, on the left side B. Products: resulting substances - what you end with, on the right side Reactants Products
Endothermic vs. Exothermic Endothermic vs. Exothermic Calcium Chloride vs. Sodium Bicarbonate… who will win the temperature war??? Turn into me: Half sheet of paper
1. Synthesis: 2 substances combine to form 1 substance A + B -> AB 2. Decomposition: 1 substance breaks down (decomposes) to 2 substances AB -> A + B (opposite of synthesis) 3. Single Displacement: 1 element replaces another A + BC -> AC + B 4. Double Displacement: positive ion of one compound replaces positive ion of another AB + CD -> AD + CB
1.4Al + 3O 2 --> 2Al 2 O 3 2.Ca(OH) 2 --> CaO + H 2 O 3.Zn + CuSO 4 --> ZnSO 4 + Cu 4.Cl 2 + 2KBr --> 2KCl + Br 2 5.BaCl 2 + Na 2 SO 4 --> 2NaCl + BaSO 4 6.2H 2 + O 2 --> 2H 2 O Synthesis Decomposition Single Displacement Double Displacement Synthesis
Label the following equations: (4types) (4types) 1.Zn + HCl ZnCl 2 + H 2 2. Fe + O 2 Fe 2 O 3 3. SiO 2 + HF SiF 4 + H 2 O 4. FeS + HCl H 2 S + FeCl 2 5. In lab yesterday, what gas produced the signature popping sound?In lab yesterday, what gas produced the signature popping sound? Single Displacement Synthesis Double Displacement FLASHBACK
You will be conducting reactions to produce 5 different common gases and observe their chemical and physical properties. A.NaHCO 3 + HCl NaCl + H ______ B.Cu + 4HNO 3 Cu(NO 3 ) 2 + 2H _____ C.NH 4 Cl + NaOH NaCl + H ______ D.2H 2 O 2 2H 2 O + ____ E.Mg + 2HCl MgCl 2 + ____ CO 2 NO 2 NH 3 O2O2 H2H2
Chemical reaction - is the process of changing reactants to products by a chemical change Chemical reactions are symbolized by Reactants Products (s) solid; (l) liquid; (g) gas; (aq) aqueous are the physical states of the reactants and products
___Mg (s) + __ O 2(g) __ MgO(s) 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. 22
We use subscripts to balance compounds CaCl 2 subscripts cannot be changed We use coefficients to balance equations 2 NaCl + _ Ca(OH) 2 2 NaOH + __ CaCl 2
Goal: to get the same number of atoms on both sides of the equation __ Al + __ O 2 ___ Al 2 O 3 __ NaCl __ Na + __ Cl 2 __ Li + __ H 2 O __ LiOH + __ H 2
A.A balanced chemical equation represents the process of a chemical reaction in which atoms are rearranged but not created or destroyed. B.By balancing chemical equations, you show that mass is conserved… Law of Conservation of Mass!
Mass is neither created nor destroyed in an ordinary chemical or physical reaction Mass of Reactants = Mass of Products
LAB: Looking at the… Law of Conservation of mass!!!
Balance the following equations: 1.___Zn + ___HCl ___ZnCl 2 + ___H 2 2. ___Fe + ___O 2 ___Fe 2 O 3 3. ___SiO 2 + ___HF ___SiF 4 + ___H 2 O 4. ___FeS + ___HCl ___H 2 S + ___FeCl 2 5.What is the overall goal of balancing equations? FLASHBACK
Balance the following equations: 3. __BeCl 2 + __KOH __Be(OH) 2 +__KCl 4. __S 8 + __ O 2 __ SO 3 5. __H 3 PO 4 + __Mg(OH) 2 __Mg 3 (PO 4 ) 2 + __H 2 O 1. __S 8 + __O 2 __SO 2 2. __ HgO __Hg + __ O 2 FLASHBACK
Reaction Rates! Reactions occur when particles of reactants collide with energy
1.Temperature: higher temperature, reaction rate increases 1.Particles moving faster, more collision between particles 2.Concentration: when reactants are more concentrated, rate of reaction increases 1.More particles mean more collisions
3. Surface Area: more surface area, reaction rate increases 4. Catalyst: presence of catalyst speeds up reaction without being permanently changed [Inhibitor: slows down a reaction] Video!
EOC WORKBOOK Pg. 45 [# 2-6] Pg. 46 [# 1-6]
Make some observations of salt under a microscope!! arkID=4&DocID=173 arkID=4&DocID=173