January 15, 2014Brain Bender

What does the prefix “poly” mean? Considering that, what do you think a polyatomic ion is?

Naming Ionic Compounds with Polyatomic Ions

Complex Ionic Compounds

Polyatomic Ions: “Poly” – many/multiple/more than

one

Polyatomic ions – ions that are made up with more than one atom Examples: NO3

-1 SO4-2 MnO4

-1 C2H3O2

-1

_These are compounds that act just like an individual element

Complex Ionic Compounds Any ionic compound that contains

three or more elements.

It can ONLY occur if there is a polyatomic ion present in the compound.

This is your list, please do not lose it

Let’s Practice: Identify the compounds with

polyatomic ions:• Hint: Look for 3 or more different atoms in

the compound.

NaCl Co(CO3)2 Li2SO4

CsNO3 MgO Cr3(PO4)2

Rules for naming Complex Ionic Compounds:

1. Name the first element directly off the periodic table, IF IT IS A METAL

*Remember to identify the charge of any transition metal using roman numerals

2. Name the second element, IF IT IS A NONMETAL, by changing the ending to -ide

3. If either of the elements is a polyatomic, name it directly off the polyatomic list, replacing step 1 or 2.

Na2CO3

Sodium Carbonate

Naming Complex Ionic Compounds:

1. Name the first element directly off the periodic table, IF IT IS A METAL

*Remember to identify the charge of any transition metal using roman numerals

2. Name the second element, IF IT IS A NONMETAL, by changing the ending to -ide

3. If either of the elements is a polyatomic, name it directly off the polyatomic list, replacing step 1 or 2.

NH4ClAmmonium Chloride

Naming Complex Ionic Compounds:

When we need multiple polyatomic ions to create a neutral compound, ( ) are used around the polyatomic ion.

The subscript is placed OUTSIDE of the ( )

The polyatomic ion MUST be treated as ONE atom….it is a unit that CANNOT be separated.

Ca+2 ClO3-1

Ca(ClO3)2

Calcium Chlorate

Let’s Practice:Compound Metal (or

polyatomic)

Nonmetal (or

polyatomic)

Compound Name:

NH4ClO3

Fe(NO3)2

Mg3(PO4)2

(NH4)2O

Mn(C2H3O2)3

Al(OH)3

Rules for writing compound formulas:

1. Write out the ions for each of the elements/polyatomic present

2. Write the charge with each ion present

3. Drop the signs (+/-)4. Swap the numbers5. Simplify if necessary

Sodium PhosphateNa+1 PO4

-3

Na3PO4

Here’s another example:

1. Write out the ions for each of the elements/polyatomic present

2. Write the charge with each ion present

3. Drop the signs (+/-)4. Swap the numbers5. Simplify if necessary

Aluminum CarbonateAl+3 CO3

-2

Al2(CO3)3

Let’s Practice:Compound Name Metal (or

polyatomic) symbol and

charge

Nonmetal (or

polyatomic) symbol and

charge

Compound

Beryllium Nitrate

Chromium (II) Hydroxide

Gallium Chlorate

Ammonium Carbonate

Zirconium (III) Sulfate