• 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 atomsTo 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!
CaCl2
Calcium ion will give up its outer electrons to both chlorine atoms
Ca
ClCl+2
-1 -1
Mg
BrBr+2
MgBr2
H
OH
Oxygen only needs two electrons so hydrogen shares its one valence electron so that both atoms fill their outer shells.
Weaker bonds form
H2O
Ionic vs. Covalent
Video
Shows only valence electrons of atom with dots around the element's symbol
What’s the point?
P=1
N=0 1 e- H
P=20
N=20 Ca2 e- 8 e- 8 e- 2 e-
Nitrogen: N
Strontium: Sr
Water: H2O
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. 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
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 23th) for a Chemistry Rap Video!
Covalent Structures: make molecules and SHARE 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!
A. When 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
What happens if it is not the neutral element.. But the ion??
e- diagram lose or gain e-? new (ion) e- diagram
Na
Cl
Mg
SECTION 1 REVIEW Pg. 606 # 4, 5
CHAPTER REVIEWPg. 626 # 4-6, 11, 14, 17, 18
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.
EOC WORKBOOK!!!EOC WORKBOOK!!!
Pg. 38 (all)Pg. 38 (all)
Pg. 39 (all)Pg. 39 (all)
Pg. 36 (all)Pg. 36 (all)
Pg. 37 (all)Pg. 37 (all)
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).
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 used2. Subscript: shows how many of the individual
atoms are presentex. 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)
The chemical symbols and numbers indicating the number of atoms contained in the basic unit of a substance
C6H12O6
Carbon = 6 atomsHydrogen = 12 atoms
Oxygen = 6 atoms
How many atoms of each element are present in 3 molecules of glucose?
C=18 H=36 O=18C=18 H=36 O=183 C6H12O6
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 = AlF3
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 compound’s 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
–ideEXAMPLE: NaCl = sodium chloride
cationcation anionanion Balance Balance formulaformula
Compound Compound namename
Cs+1,cesium F-1,fluorine
Ba+2, barium Cl-1,chlorine
Al+3, aluminum S-2, sulfur Aluminum sulfide
Cesium Fluoride
Barium chloride
CsF
BaCl2
Al2S3
Uses prefixes!!!!Number of atoms
prefix
1 Mono-2 Di-3 Tri-4 Tetra-5 Penta-6 Hexa-7 Hepta-8 Octa-9 Nona-10 Deca-
If there is only one atom of the first element, it does not get a prefix
EX: BF3= boron trifluoride
Dihydrogen monoxide Dihydrogen monoxide = ????= ????
Dihydrogen Monoxide!!!!!!!!Why????Why????
If H20 is water, what is H204?
Drinking, bathing, washing,
swimming…All kinds of things!
What’s 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 it’s oxidation number2.A total of 6 IONIC COMPOUND formulas 3.AND the name of those compounds
My IonMy Ion What I am What I am bonding withbonding with
Chemical Chemical FormulaFormula
NameName
Fe+2 O-2 FeO Iron Oxide
Try these covalent molecules…
CO CO2
N5H8
TeBr2
Si3S7
Carbon Carbon monoxidemonoxideCarbon dioxideCarbon dioxidePentanitrogen octahydridePentanitrogen octahydride
Tellurium dibromideTellurium dibromideTrisilicon Trisilicon heptasulfideheptasulfide
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
FLASHBACK
COVALENT:NONO2
N2OIONIC:
NaFZnClCaCl2
1. Electron Dot Diagram: 2. Pictorial Diagrams:
Hydrogen: H
Oxygen:
Water: H2O
H
O
OH
HCovalent Covalent bonds!bonds!
Chemical Changes
and Chemical Reactions
Occur when the size or shape of the substance is changed
Occasionally, the color can change, tooRegardless, 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 Occurs when there is a change in the arrangement of atoms so that arrangement of atoms so that a different a different substance with different properties is substance with different properties is producedproduced
Very often, Very often, there is some there is some kind of kind of evidence evidence ((for example, for example, the formation the formation of a gasof a gas))
1. Formation of a gas2. 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 formed3. Energy change4. Color change5. 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 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.
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-Seltzer2. 1 film canister3. 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 ReportYou are to write a brief lab report on your experience…
- Skip lines between headings- Full sentences! Alka seltzer
TitleHypothesis: (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
Naming:2) P2O5 ___________________________3) Mg3N ___________________________5) SiO2 ____________________________6) BaCl2 _______________________________8) B2P9 _____________________________________
Formulas:14) aluminum nitride ____________________16) disulfur pentaphosphide ____________________17) potassium sulfide __________________________18) rubidium iodide ____________________________20) hexacarbon dichloride ______________________
Chemical Reactions and Chemical Reactions and Equations:Equations:
What do they mean?What do they mean?What do they show?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 Everyday Exothermic and Endothermic ReactionsEndothermic Reactions
Instant Cold Packs
Instant heat packs
•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.
•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 Reactants Products 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 -> AB2. Decomposition: 1 substance breaks down
(decomposes) to 2 substancesAB -> A + B (opposite of
synthesis)3. Single Displacement: 1 element replaces another
A + BC -> AC + B4. Double Displacement: positive ion of one
compound replaces positive ion of anotherAB + CD -> AD + CB
1. 4Al + 3O2 --> 2Al2O3
2. Ca(OH)2 --> CaO + H2O
3. Zn + CuSO4 --> ZnSO4 + Cu
4. Cl2 + 2KBr --> 2KCl + Br2
5. BaCl2 + Na2SO4 --> 2NaCl + BaSO4
6. 2H2 + O2 --> 2H2O
SynthesisSynthesis
DecompositionDecomposition
Single DisplacementSingle Displacement
Single DisplacementSingle Displacement
Double Double DisplacementDisplacement
SynthesisSynthesis
Label the following equations: (4types)
1. Zn + HCl ZnCl2 + H2
2. Fe + O2 Fe2O3
3. SiO2 + HF SiF4 + H2O
4. FeS + HCl H2S + FeCl2
5. In lab yesterday, what gas produced the signature “popping” sound?
Single Displacement
Synthesis
Double Displacement
Double Displacement
FLASHBACK
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 + 2H20 + 2 _____
C. NH4Cl + NaOH NaCl + H20 + ______
D. 2H2O2 2H2O + ____
E. Mg + 2HCl MgCl2 + ____
CO2
NO2
NH3
O2
H2
Section ReviewPg. 645 #1, 3
EOC REVIEWPg. 656#1-5,
11, 15
FLASHBACK
EOC WORKBOOKPg. 43 [all]
FLASHBACK
Chemical reaction - is the process of changing reactants to products by a chemical changeChemical 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) + __ O2(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.
2 2
We use subscripts to balance compounds
CaCl2
subscripts cannot be changed
We use coefficients to balance equations
2 NaCl + _ Ca(OH)2 2 NaOH + __ CaCl2
Goal: to get the same number of atoms on both sides of the equation
__ Al + __ O2 ___ Al2O3
__ NaCl __ Na + __ Cl2
__ Li + __ H2O __ LiOH + __ H2
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 Mass is neither created nor destroyed in an ordinary chemical or physical in an ordinary chemical or physical
reactionreaction
Mass of Reactants = Mass of Products
LAB: Looking at the…Law of Conservation of mass!!!
Balance the following equations:1. ___Zn + ___HCl ___ZnCl2 + ___H2
2. ___Fe + ___O2 ___Fe2O3
3. ___SiO2 + ___HF ___SiF4 + ___H2O
4. ___FeS + ___HCl ___H2S + ___FeCl2
5.What is the overall goal of balancing equations?
FLASHBACK
Balance the following equations:
3. __BeCl2 + __KOH __Be(OH)2 +__KCl
4. __S8 + __ O2 __ SO3
5. __H3PO4 + __Mg(OH)2 __Mg3(PO4)2 + __H2O
1. __S8 + __O2 __SO2
2. __ HgO __Hg + __ O2
FLASHBACK
Reaction Rates!Reaction Rates!
Reactions occur when Reactions occur when particles of reactants particles of reactants collide with energycollide with energy
1. Temperature: higher temperature, reaction rate increases1. Particles moving faster, more collision
between particles
2. Concentration: when reactants are more concentrated, rate of reaction increases1. 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 WORKBOOKPg. 45 [# 2-6]Pg. 46 [# 1-6]
Make some observations of salt under a microscope!!
http://www.sciencenetlinks.com/lessons.php?BenchmarkID=4&DocID=173http://www.sciencenetlinks.com/lessons.php?BenchmarkID=4&DocID=173http://www.mos.org/sln/sem/sem.html
