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: