1.combination of atoms to form a compound (with different properties) 2. determined by electrons in...
TRANSCRIPT
UNIT 3:BONDING
WHAT IS BONDING???
1.Combination of atoms to form a compound (with different properties)
2. Determined by electrons in atoms3. Why bond?
To increase stability To decrease energy To fill valence!!
4. A balanced combination of positive and negative ions.
5. Simplest whole number ratio
OCTET RULE
Chemical compounds form so that each element has a full octet of electrons in its highest energy level.
This can happen through gaining, losing, or sharing electrons.
AGENDA 11/17/14
Review Unit 5 Tests Redo policy Before Thanksgiving Break?
Review Ionic Compounds Properties
Continue Puzzle Piece activity Let’s Clarify the directions
HW: Finish analysis questions for Activity
TYPES OF BONDING Ionic Bond
The chemical bond resulting from electrostatic attraction between positive and negative ions.
Metals tend to lose electrons and form cations.
Nonmetals tend to gain electrons and form anions
IONIC COMPOUND PROPERTIES
Solid state is a crystalline structure Hard, brittle solids High melting point
NaCl is 801oC Do not conduct electricity as solids Do conduct as liquids and solutions Not discreet molecules, instead called
formula units
Identify charges of both the cation and the anion.
Collect puzzle pieces that correspond to the ions.
Adding more of only those charges, continue adding pieces until you have a complete and stable compound.
Puzzle Method
EXAMPLES….
Sodium Oxide Calcium Sulfide Aluminum Chloride
LET’S CLARIFY
Each pair needs new puzzle pieces The goal of fitting the pieces together is
to make a complete rectangle or square. Cations can only bond with anions!!
Your job is to make 20 combinations
Do Not try the Naming Yet!!!
AGENDA 11/18/14
Finish Formula Writing Lab Homework for tomorrow
Go Over Unit 5 Test Collect Formula Writing Lab (3 and 8)
1 per group Notes on writing and naming Ionic
Compounds
INTRO TO FORMULA WRITING LAB
Meet with your lab partners
Compare answers to analysis questions , and your conclusions.
Determine which of the two labs you will turn in.
Both partners names should be on the lab.
WHITE BOARDS ARE BACK!!
Get into your white board groups
One marker per group
PRACTICE FORMULA WRITING
Write the correct formula for the following cation and anion pairs:1. Na+ and Cl-
2. Mg+2 and F-
3. C-4 and H+
4. Ag+3 and O-2
5. Ag+3 and N-3
Bonus Question: Is there a pattern you notice between the charges on the ions and the subscripts in the formulas?
CRISS-CROSS METHOD
Identify charges of both the cation and the anion.
Switch the charge value to be the opposite ion’s newest subscript.
Repeat for the other ion.Example:
Ag+3 O-2
Ag2O3
ONE EXCEPTION
Ag+3 and N-3
Do the criss-cross method
If the subscripts can be reduced…reduce them!
NAMING AN IONIC COMPOUND…
Cation is always named first Cation take the name of the element
Transition metals use the formula to find the charge (Roman numeral = charge)
Anion Monatomic (only one element) end in –
ide
EXAMPLES…
CaF2
calcium fluoride Li2S
Lithium sulfide FeCl2 (This is a transition metal)
Iron (II) chloride (ferrous chloride) FeCl3 (This is a transition metal)
Iron (III) chloride (ferric chloride)
MORE EXAMPLES…
PtO2
Platinum (IV) oxide CuBr
Copper (I) bromide (cuprous bromide) Zn3N2
Zinc (II) nitride (Zn is almost always +2) Sn3P2
Tin (II) phosphide (stannous phosphide)
MORE PRACTICE…
Ca(OH)2
Calcium hydroxide NaSCN
Sodium thiocyanate Al2(CrO4)3
Aluminum chromate Mg(NO2)2
Magnesium nitrite
PRACTICE, PRACTICE, PRACTICE…
NH4Cl Ammonium chloride
Au2(CO3)3
Gold (III) carbonate Pb(CN)4
Lead (IV) cyanide FePO4
Iron (III) phosphate
AGENDA 11/18/14
Review Ionic Formula Writing Notes on Polyatomic Ions
Naming Notes on naming Covalent Compounds
Properties of covalent compounds
HW: Naming monatomic and polyatomic formulas
COVALENT MOLECULES
Bonds that exist between two non-metals Two anions!!
Both atoms want to gain electrons so they share electrons in bonds to complete their octet.
MOLECULAR SUBSTANCES
These exist between two different anions. Ex: Carbon monoxide, CO, C==O
Many different solid forms, not crystalline Relatively low melting and boiling point. Poor conductors in all states! Do not dissolve in water very well.
Organic compounds are examples of molecular substances.
NETWORK SOLIDS
Bonds between one non-metal element Ex: C60 Buckminsterfullerene Buckyballs Diamond, Graphite, and Carbon nanotubes
NETWORK SOLIDS
Different shapes in the solid form. High melting and boiling points Often hard and brittle Non-conducting solids Do not dissolve in water well
NAMING COVALENT COMPOUNDS
1. First element using full element name2. Second element name as if it were an
anion (-ide)3. Use prefixes to denote # of atoms
present for both of the elements- exception: mono is NOT used for the first element.Ex: CO Carbon monoxide
Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
PREFIXES
One mono- Two di- Three tri- Four tetra- Five penta- Six hexa- Seven hepta- Eight octa- Nine nona- Ten deca-
EXAMPLES:
N2O3
dinitrogen trioxide N2O5
Dinitrogen pentoxide Xenon tetrafluoride
XeF4
Oxygen dichloride OCl2
Diphosphorus trioxide P2O3
AGENDA 11/20/14
Review all types of naming Notes on metallic substances Practice Practice Practice
HW: Naming covalent compounds
NAME ALL OF THESE CORRECTLY!!
1. S2F3 4. PbO2
2. BeS 5. LiOH
3. CO2 6. NCl3
METALLIC BONDS: WHEN METALS COME TOGETHER
METALLIC BONDING
Metallic bonds are described as a cluster of positive metal ions surrounded by a sea of their shared valence electrons.
Metallic Bonding is the type of bonding found in metallic substances.
The positive ions remain fixed in a crystal lattice, while the loosely-held valence electrons move freely throughout the entire crystal.
Melting/boiling points between covalent and ionic compounds.
Not soluble in water.
Insert figure 8.9
A Model of Metallic Bonding
The positive metal ions are surrounded by a huge
cloud of free flowing electrons.
PROPERTIES OF METALS EXPLAINED BY THE E- SEA…
Metals are great conductors of electricity. Why?
Electricity can be described as a movement of charged particles, so if you have mobile charged particles present then electricity can flow.
For metals, the sea of electrons is basically a cloud of mobile charged particles.
METALS ARE MALLEABLE AND DUCTILE Malleable: Can be beaten into a thin
sheet Ductile: Can be pulled into a wire. Why? If you add stress you force like charges
closer together. They repel each other and move apart, but instead of shattering, the particles rearrange with the sea of electrons.
HITTING A METAL
LAST PROPERTY: METALS ARE SHINY! Metals are shiny!! Why? The valence electrons move within the “sea”
around the positive ions of the metals. When the light wave hits the electrons in the
“sea”, the light “bounces” off of them or is reflected back by the electrons.
When this light hits our eyes, the appearance we see is that the metal is shiny.
SHINY METALS: