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 3/28/11 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 ANIMATIONChemical 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 SO32- sulfite PO4

3- 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 name

Write the anion name 2nd Change the ending of the

name to –ide.

Flash Card On the front

write:

Polyatomic Ion

On the back write:

Ion consisting of many covalently bonded atoms

WBC

Zinc Fluoride Zn+2

F-1

WBC

Plumbous Bromide Pb+2

Br-1

WBC

Stannous Sulfide Sn+2

S-2

WBC

Silver Phosphide Ag+1

P-3

WBC

Lead (II) Bromide Pb+2

Br-1

Warm-Up 3/29/11Review questions: What is the

subscript in H2O? What are some mistakes to avoid (look at notes)!

Teach the teacher questions: What is one of the better board games?

Learning Targets: Balancing equations and the naming of compounds.

Flash Card On the front

write:

Polyatomic Ion

On the back write:

Ion consisting of many covalently bonded atoms (like conjoined twins)

Warm-Up 3/31/11Review: Why are conjoined twins

like polyatomic ions?

Teach the Teacher: What is the best April’s fools prank you have heard of.

Ionic and covalent bonding balancing formula units

Flash Card On the front

write:

Molecule

On the back write:

A group of atoms that are bonded together, neutral charge

Covalent BondsCovalent bonds share electronsComposed of 2 or more nonmetals (and

H)Covalent compounds are called moleculesMolecules can be polar or nonpolarPolar molecule—slightly positive and

negative at parts—but overall neutrale- are unevenly shared

Nonpolar molecule—electrons are shared equally—completely neutral

Comparing ionic and covelent compounds

Covelent compounds Ionic compounds

Smallest particles molecules cations and anions

Origin of bonding electron sharing electron transfer

Forces between particlesstrong bonds between

atomsweak attractions between

molecules

Strong attractions between anions and cations. strong

repulsions between ions of like charge

Elements present close on the periodic table widely separated on the periodic table

Metallic elements present rarely usually

electrical conductivity poor good, when melted or dissolved

state at room temperature solid, liquid, or gas solid

melting and boiling points lower higher

other names molecular compounds salts

• Polar or Nonpolar

– Polar Bonds • an unequal sharing of the e-• Due to a difference of electro-

negativity of the atoms – F is the most electronegative element

on PT

– Non-polar Bonds • an equal sharing of e- • nonpolar bond animation

– Multiple Bonds – More than one pair of electrons can be shared between atoms• Double Bonds = 2 shared pairs of e-• Triple Bonds= 3 shared pairs of e-

Chemical Bonds

Naming Covalent Compounds

Use prefixes to tell how many of each element you have.This is done because you can have

different covalent compounds containing the same elements.

Change the ending of the 2nd element to -ideEx. N2O is dinitrogen monoxide.

You can leave off the prefix mono- on the first element.Ex. NO2 is nitrogen dioxide

Not mononitrogen dioxide

Mono—1Di—2Tri—3Tetra—4Penta—5Hexa—6Hepta—7Octa—8Nona—9Deca—10

Formulas for Covalent Compounds

Use the prefixes as the subscript in the formula.

Ex. Phosphorus TrichloridePCl3

Dinitrogen TetrafluorideN2F4

Covalent or Ionic

Bond between a metal and a nonmetal

Covalent or Ionic Bond between two nonmetals

Covalent or Ionic Can be polar or nonpolar

Covalent or Ionic

H20

Covalent or Ionic

NH3

Covalent or Ionic

NaCl

Covalent or Ionic Roman Numerals are used to

indicate the oxidation state of the metal cation

Covalent or Ionic Carbon tetrachloride

Covalent or Ionic Electrons are gained or lost,

or transferred from one atom to another

Covalent or Ionic

sulfur(VI) oxide

Covalent or Ionic

carbon tetrachloride

Notes to Notecard 1. Why do atoms form compounds?

2. After two elements combined in a chemical reaction, is the new substance the same as the elements that made it? (Yes or No)

3. Which type of bond contains only a metal?

4. A trick for writing formulas is to crisscoss charges, but what do you not put in the formula?

5. What are the little written ionic charges called? (opposite of superscript.)