Writing formulas for multivalent ionic compounds

Writing formulas for multivalent ionic compoundsWriting formulas for multivalent ionic compounds

• Transition metals have the ability to form more than one cation

• Therefore, a roman numeral is placed in the name to signify the charge on the cation

• Example:– Iron (III) Chloride

• Write the formula?

• Transition metals have the ability to form more than one cation

• Therefore, a roman numeral is placed in the name to signify the charge on the cation

• Example:– Iron (III) Chloride

• Write the formula?

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Writing formulas for mulitvalent ionic compoundsWriting formulas for mulitvalent ionic compounds

• Write formulas for the following:• Copper (I) Oxide• Copper (II) Oxide

Answers - Cu2O CuO

• Write formulas for the following:• Copper (I) Oxide• Copper (II) Oxide

Answers - Cu2O CuO

Naming compounds with multivalent metalsNaming compounds with multivalent metals

• If the metal is in group B it requires a roman numeral in the name.

• You will have to deduce the roman numeral based on the formula.

• Example– Name CoI2

• Answer - Cobalt (II) Iodide

• If the metal is in group B it requires a roman numeral in the name.

• You will have to deduce the roman numeral based on the formula.

• Example– Name CoI2

• Answer - Cobalt (II) Iodide

Naming compounds with multivalent metalsNaming compounds with multivalent metals

• Deducing the roman numeral• Multiply the charge on the anion by the

number of anions and then divide by the number of cations to get the roman numeral.

• Write the names for Fe2S3 SnO2

• Answers - – Iron (III) Sulfide Tin (IV) Oxide

• Deducing the roman numeral• Multiply the charge on the anion by the

number of anions and then divide by the number of cations to get the roman numeral.

• Write the names for Fe2S3 SnO2

• Answers - – Iron (III) Sulfide Tin (IV) Oxide

• Take ten minutes and work on sections 5 and 6 on the back side of your worksheet.

• Take ten minutes and work on sections 5 and 6 on the back side of your worksheet.

Polyatomic IonsPolyatomic Ions• A group of atoms that carry a charge• Examples:

– SO42- NO3

1-

• Names of polyatomic ions that contain oxygen will end in -ate or -ite

• -ite is one less oxygen then ate• Example

– Sulfate is SO42- Sulfite is SO3

2-

– Chlorate is ClO31- Chlorite is ClO2

1-

• Other polyatomic ions– NH4

1+ Ammonium CN1- cyanide– OH1- Hydroxide

• A group of atoms that carry a charge• Examples:

– SO42- NO3

1-

• Names of polyatomic ions that contain oxygen will end in -ate or -ite

• -ite is one less oxygen then ate• Example

– Sulfate is SO42- Sulfite is SO3

2-

– Chlorate is ClO31- Chlorite is ClO2

1-

• Other polyatomic ions– NH4

1+ Ammonium CN1- cyanide– OH1- Hydroxide

Writing formulas using polyatomic ionsWriting formulas using polyatomic ions

• The polyatomic ion is treated as one unit.

• Balance the charges• Place parenthesis around the

polyatomic ion if there is more than one• Example

– Write the formula for Iron (II) Nitrate

• Fe2+ and NO31- combines to make

Fe(NO3)2

• The polyatomic ion is treated as one unit.

• Balance the charges• Place parenthesis around the

polyatomic ion if there is more than one• Example

– Write the formula for Iron (II) Nitrate

• Fe2+ and NO31- combines to make

Fe(NO3)2

Naming using Polyatomic ionsNaming using Polyatomic ions

• Name the metal than name the polyatomic ion. If you need a roman numeral; include it.

• Treat the polyatomic ion as one unit (as if it were one atom)

• Example - Name CuSO4

• Copper (II) Sulfate

• Name the metal than name the polyatomic ion. If you need a roman numeral; include it.

• Treat the polyatomic ion as one unit (as if it were one atom)

• Example - Name CuSO4

• Copper (II) Sulfate

Exceptions for roman numeralsExceptions for roman numerals

• Silver, Cadmium and Zinc do not get roman numerals.

• Ag is always +1, Cadmium and Zinc are always +2

• Tin and Lead need roman numerals. They are multivalent (multiple oxidation states)

• Silver, Cadmium and Zinc do not get roman numerals.

• Ag is always +1, Cadmium and Zinc are always +2

• Tin and Lead need roman numerals. They are multivalent (multiple oxidation states)

Naming AcidsNaming Acids

• Memorize• HCl - Hydrochloric Acid• H2SO4 - Sulfuric Acid• HNO3- Nitric Acid• H3PO4 - Phosphoric Acid• Note - Acids give off H1+ (Hydrogen ions)

and bases give off OH1- ions• What do you get when an acid and base

combine?

• Memorize• HCl - Hydrochloric Acid• H2SO4 - Sulfuric Acid• HNO3- Nitric Acid• H3PO4 - Phosphoric Acid• Note - Acids give off H1+ (Hydrogen ions)

and bases give off OH1- ions• What do you get when an acid and base

combine?

Name the cation firstthen name the anion

Example: Lithium FuorideMagnesium Carbonate

No

Name the cation firstPlace a roman numeral

Name the anionExample: Iron (II) Sulfate

Yes

Does the compound contain amultivalent ion?

aka - transition metal orgroup B element

Ionic

Yes

Use prefixes to representthe number of atoms.

Example: H2O Dihydrogen MonoxideCO2 Cabon Dioxide

Molecular

No

Is there a metal?

Naming Compounds

Name the cation firstthen name the anion

Example: Lithium FuorideMagnesium Carbonate

No

Name the cation firstPlace a roman numeral

Name the anionExample: Iron (II) Sulfate

Yes

Does the compound contain amultivalent ion?

aka - transition metal orgroup B element

Ionic

Yes

Use prefixes to representthe number of atoms.

Example: H2O Dihydrogen MonoxideCO2 Cabon Dioxide

Molecular

No

Is there a metal?

Naming Compounds

Check for understandingCheck for understanding

• Name or write the formula for:– Potassium Sulfate– Chromium (III) Cyanide

– Fe(ClO3)3

– CuCl

• Answers– K2SO4 Cr(CN)3

– Iron (III) Chlorate– Copper (I) Chloride

• Name or write the formula for:– Potassium Sulfate– Chromium (III) Cyanide

– Fe(ClO3)3

– CuCl

• Answers– K2SO4 Cr(CN)3

– Iron (III) Chlorate– Copper (I) Chloride

• Now finish your worksheet and work on your homework.

• Get help• Make sure and check your answers on-

line. You will be writing formulas all year and doing math based on these formulas. You get the formula wrong you get the math wrong.

• Now finish your worksheet and work on your homework.

• Get help• Make sure and check your answers on-

line. You will be writing formulas all year and doing math based on these formulas. You get the formula wrong you get the math wrong.