3.2 Names and Formulas of

Ionic Compounds

Objectives

By the end of the lesson you should be able

to:

Describe simple and complex ions

Name and make all types of ionic

compounds

WARM UP! Counting Atoms Practice

Formula # of

Atoms Formula

# of Atoms

1) NaCl 4) Mg(OH)2

2) HNO3 5) (NH4)2O

3) H2SO4 6) NH4NO3

Complex and Simple Ions

Simple Ions: one atom with a charge

H+ S-2 Cu+1 Cu+2

Complex Ions: more than one atom with

an overall charge

Called polyatomic ions

Listed on pg 92 in your textbook

SO4-2 NO3

-1 NH4+1

Remember…

ALL ELEMENTS WANT TO HAVE FULL OUTER

SHELLS!

The combining capacity (AKA: charge) tells

you how many electrons have been

lost/gained to get a full outer shell

Names and Formulas

Naming compounds: involves writing out

the entire name for each element in the

compound

Compound and symbols given make

name!

Formulas: involve using symbols of each

element to make the compound

Name given make compound with

symbols

Ionic Compounds Always involve a positive charge (metal) and a

negative charge (non-metal)

Electrons are always transferred from the positive to

the negative

Create ions because losing and gaining electrons

(charges result)

Rules for Naming Ionic

Chemical Compounds

1. Write the name of the metal element 1st

2. Write the name of the non-metallic

element 2nd (is farther right on the

Periodic Table)

3. Change the ending of the non-metallic

element to “ide”

Example: CaCl2

Calcium chloride

Chemical Formulas of Ionic

Compounds

Formulas contain symbols to identify each

ion in an ionic compound, as well as the

relative numbers of ions in the compound.

Example: NaCl – 1 sodium:1chlorine

CaF2 – 1 calcium:2 fluorines

Note: Relative numbers of each ion is a

subscript to the right of the symbol

Naming Ionic Compounds

Metal always first; name never changes

Non-metal second; ending becomes “ide”

EX:

NaCl = sodium chloride

MgF2 = magnesium fluoride

Al2O3 = aluminum oxide

Your Turn!

Practice Problems pg. 86

Rules for Writing Ionic

Chemical Formulas

1. Write the symbol of the metal 1st

2. Write the symbol of the non-metal 2nd

3. Write in the ion charges of both symbols as superscripts to the top right of each symbol (found on the Periodic Table)

4. Drop the +/- signs and cross the ion charges and write as subscripts (to the bottom right of the symbol). The number 1 is never written.

5. Reduce, if necessary

Example of a Metal & Non-

metal Combining

1. Calcium chloride (write the

symbols)

2. Ca Cl (superscript combining capacities)

3. Ca 2+

Cl 1-

4. Ca 2+

Cl 1-

(drop the +/- signs and cross combining

capacities)

5. CaCl2

Ionic Compound Formulas

1. Get symbol and charge

Charges are the same skip to step 2

If charges are different “swap and drop”

2. Combine

Your Turn!

Practice Problems pg. 87

Multivalent Ionic Compounds Multivalent = more than one combining

capacity

Found in the Transition Metals section

Same naming as Ionic Compounds

BUT use a roman numeral to show which combining capacity is used

I II III IV V VI VII VII

1 2 3 4 5 6 7 8

Multivalent Ionic Compound Formulas (Roman Numeral given)

1. Get symbol and possible charges

2. Choose appropriate ion (from Roman Numeral)

Charges are the same skip to step 2

If charges are different “swap and drop”

3. Combine

Your Turn!

Practice Problems pg. 89

Compounds Containing

Multivalent Metals

Notice that some metallic elements have

more than 1 ion charge.

We need to use Roman Numerals to

indicate which combining capacity is

used.

E.g. Copper (II) chloride = Cu +2

E.g. Copper (I) chloride = Cu +1

Naming Note:

Multivalent Metal

Use the Roman Numeral equal to the ionic charge to indicate which combining capacity was used

E.g. CuCl2

Cu1+ or Cu2+

Copper (II) chloride

E.g. Fe2O3

Fe3+ or Fe2+

Iron (III) oxide

You need to reverse

cross to find combining

capacities.

Naming Multivalent Ionic Compounds (no Roman Numeral given)

1. Get possible charges

2. Determine which charge will give the correct

formula (reverse swap and drop)

3. Write the name same as you did with Ionic

Compounds

4. Add the appropriate Roman Numeral between

the metal and non-metal

Your Turn!

Practice Problems pg. 90

Naming Polyatomic Ionic

Compounds

Usually seen in more complicated compounds

List of Polyatomic Ions is found in your textbook on pg.92 and on the back of your PT

1. Look up both names

2. Check for multivalent charges and insert Roman Numerals if need be

3. Combine

Reactions involving

Polyatomic Ions (Radicals)

E.g. Ammonium sulfide Ammonium = NH

4 1+ (1+ is the ion charge)

(given on the back of the Periodic Table)

When NH4 1+

S 2- combine, the NH4

stays together

So, NH4 1+

S 2-

You need to put brackets around NH4 so you can separate the digits

(NH4)2 S

Polyatomic Ionic Compound

Formulas

1. Get symbol and possible charges

If same skip to step 2

If different “swap and drop”

2. Combine – use brackets if need be for

polyatomic ions ONLY

Radicals & Roman Numerals

Copper sulfate

Copper (II) sulfate

1. Cu SO4

2. Cu2+

SO4

2-

3. Cu2+

SO4

2-

4.Cu2(SO4)2 the 2’s reduce

5.Cu(SO4) brackets can be dropped

Your Turn!

Practice Problems pg. 91

Homework:

Pg. 95 # 1-6

Types of Chemical Reactions

Exothermic – energy

is released from the

reaction

Example: Atomic

blast

Memory Tip:

Exo – starts with the

letters “ex” similar to

exit

Types of Chemical Reactions

Endothermic – energy is absorbed in order for the reaction to occur

Example: cooking eggs

Memory Tip: Endo – starts with the

letters “en” similar to enter