Warm-up 3/21/11Review questions: List as many elements

as you can think of. Then list as many compounds as you can think of.

Teach the teacher questions: If you could start a band what kind of band would you start, what would you call it, and what part would have in it (play guitar, sing, ect.).

Learning Targets: By the end of the class you should know: what happens when elements combine

the two different kinds of bondshow to balance cations and anions for a

chemical bond

Chemical BondsBonding isn’t just for people.

Why do atoms form compounds? TO BECOME STABLE!!What does stable mean to an atom?

Full set of valence electrons Atoms want to have the electron

configuration of a noble gas Atoms will gain, lose or share

electrons in order to obtain a full set of valence electrons

Chemical bonding

Combining ElementsThe chemical & physical properties of

the elements are different than the properties of the compound they make up

Na + Cl2 → NaCl

Reaction of Sodium with Chlorine & Hydrogen with Oxygen

→

Types of BondsIonic Bonds

Contain a metal & a nonmetal (at least 1 of each)

Electrons are gained or lostEx. Salt, NaCl

Covalent BondsContain 2 or more nonmetals or hydrogenElectrons are sharedEx. Water, H2O

Ionic BondingIn an ionic bond, one atoms gives

electrons to another atom.When atoms combine this way, it is

called a formula unit.Ex. NaCl is a formula unit

The charge of a formula unit is always 0.

The positive and negative charges must always balance each other.

FormulasChemical Formula—tells what elements

a compound contains and the exact number of the atoms of each element.Ex. NaCl has 1 atom of sodium & 1 atom of

chlorineEx. H2O has 2 atoms of hydrogen and 1 atom

of oxygen.A subscript (small # written below) is

written after a symbol to tell how many atoms of that element are in the compound.

Rules for FormulasWrite the cation (metal) first. Write the anion (nonmetal) second.

The net ionic charge is zero.Use subscripts to indicate multiple ions.

Write the formula unit in the lowest whole number ratio.

A trick for formula unitsWrite both ions with their charges as superscripts. Cu3+ & O2-

Crisscross the charges to make the subscripts in the formulaDo not put + or – in the formula

Cu3+ & O2-

Cu2O3

Silver Chloride

AgCl

Ag+1 Cl-1

Zinc Phosphide

Zn3P2

Zn+2 P-3

Aluminum Oxide

Al2O3

Al+3 O-2

Warm-Up 3/24/11Review: Give an example of a

formula unit.

Teach the Teacher: What is the best holiday? Are you going to the pow wow?

Flash cardOn the front

write:

subscript

On the back write:

H2O (submarine)

Flash card On the front:

Ionic Bonding

On the back:

When an element gains or loses an electron

Flash Card On the front:

Covalent bonding

On the back:

When atoms share electrons

Warm-Up 3/25/11 Review questions: What is an ionic bond?

(use your flash cards)

Teach the teacher questions: Would you rather be stuck in an elevator with wet dogs or wet cats?

  Learning Targets: By the end of the class

you should know: polyatomic ions

Practice with Chemical Formulas Common Name Chemical Formula Types & Number

of Elements involved Sand SiO2

Milk of Magnesia Mg(OH)2

Sucrose C12H22O11

Vinegar HC2H3O2

Ethanol C2H5OH

→

Types of Bonds IONIC BONDS

between metals & nonmetals

Electrons form a give take relationshipmetals give e- (cation) nonmetal take e- (anion)

Held together by attraction of opposite charges

IONIC ANIMATION

Chemical Bonds

Table Polyatomic IonsPolyatomic Ions

The prefix poly- means many in Greek. ion consisting of a molecule with many

covalently bonded atoms act as a single unitpolyatomic ion is also referred as a radical Usually end in –ate & –ite -ide usually indicates binary compounds

+1 CHARGE -1 CHARGE -2 CHARGE -3 CHARGE

ion name ion name ion name ion name

NH4+ ammonium NO2

- nitrite CO32- carbonate PO3

3- phosphite

H3O+ hydronium NO3- nitrate SO3

2- sulfite PO43- phosphate

Hg22+ mercury(I) OH- hydroxide SO4

2- sulfate

CH3COO-

C2H3O2- acetate S2O3

2- thiosulfate

CN- cyanide CrO42- chromate

CNS- thiocyanate Cr2O72- dichromate

MnO4- permanganate

ClO3- chlorate

ClO4- perchlorate

IO2- iodite

IO3- iodate

Oxidation number—the charge of an ion

1+

2+ 3+ 3- 2- 1-

Multiple Oxidation Numbers

Some metals (other metals & transition metals) can have more than 1 oxidation number.

If an element can have more than 1 oxidation number, the charge of the ion is written as a roman numeral in parentheses.Ex. Copper (I) ion is Cu1+

Copper (II) ion is Cu2+

Mistakes to AvoidRoman numerals are not

written in the formula

Charges are not written in the formula

Don’t drop polyatomic subscripts

Hydroxide, OH, needs parentheses to indicate multiples.

Cu(II)O CuO

K+1Br-1 KBr

CaNO2 Ca(NO3)2

CaOH2 Ca(OH)2

Rules for Naming Ionic Compounds Group A Elements

Write the cation name 1st Cation name is the same as

the element nameWrite the anion name 2nd

Change the ending of thename to –ide.

Flash Card On the front

write:

Polyatomic Ion

On the back write:

Ion consisting of many covalently bonded atoms

WBCZinc Fluoride Zn+2

F-1

WBCPlumbous Bromide Pb+2

Br-1

WBCStannous Sulfide Sn+2

S-2

WBCSilver Phosphide Ag+1

P-3

WBCLead (II) Bromide Pb+2

Br-1