multivalent ionic compounds

Ions of some transition elements can have more than one possible charge.

Such elements are called MULTIVALENT species.

For example, what are the 2 possible charges for copper – Cu?◦_________________◦_________________

WE use ROMAN NUMERALS to indicate the type of charge on these multivalent ions.

◦1+ I◦2+ II◦3+ III◦4+ IV◦5+ V◦6+ VI

ONLY USE WITH MULTIVALENT IONS!

MULTIVALENT IONIC COMPOUNDS

RULES1. Use ROMAN NUMERALS to

determine the ION CHARGE of the MULTIVALENT ION.

2. If ROMAN NUMERAL are NOT given, use the charge found on the top in each box on the table.

EXAMPLE: copper (II) oxide

_________________________

GIVEN NAME, WRITE FORMULA

lead (IV) sulfide_________________________

tin sulfide_________________________


Do the sheet on the following page!

Remember to ONLY use the ROMAN NUMERAL with the MULTIVALENT IONS!!!

HOMEWORK!!!

RULES1. Write the names of the ions.

2. Write the ROMAN NUMERAL for the MULTIVALENT ION. There are 2 METHODS:

1. METHOD 1 Charges must add up to zero.

2. METHOD 2 Charge of Anion X Subscript of AnionSubscript of Cation

GIVEN FORMULA, WRITE NAME

PbI2 _________________________

Fe2O3 _________________________


CuCl _________________________

MnO2 _________________________


Do the next 2 sheets for homework!

Remember, doing some workings can help prevent any mistakes!!!

HOMEWORK!!!

DEFINITION:◦Polyatomic ions are GROUPS OF ATOMS acting as 1 ION, carrying an OVERALL CHARGE.

On the back of your periodic table, there is a POLYATOMIC ION TABLE.

Endings of polyatomic ions are easily recognizable as they are often –ATE or –ITE, providing a good clue.

EXAMPLES:

◦nitrate ________◦nitrite ________◦cyanide ________◦hydroxide ________◦bicarbonate ________◦chlorate ________◦carbonate________◦sulfate ________◦phosphate ________◦ammonium ________◦acetate ________

POLYATOMIC IONIC COMPOUNDS

lithium sulfate _____________________

ammonium carbonate_____________________


hydrogen dichromate_____________________

sodium acetate _____________________


HNO3 _____________________

NaOH _____________________


KMnO4_____________________

Cu2SO4_____________________


hydrogen carbonate is AKA bicarbonate HCO3

-

hydrogen sulfate is AKA bisulfate HSO4-

tetraborate B4O72-

silicate SiO32-

glutamate C5NH8O4-

SOME OTHER NAMES . . .

Do the next 2 Sheets for homework!!!

Remember to use the crossover method for charges.

You may find it helpful to use BRACKETS around ALL polyatomic ions when writing the formulae.

HOMEWORK!!! ☻☺

1. Simple Ions

Names Formulas- write the name of the positive ion - determine the charge on each ion

- write the name of the negative ion - cross over the charges to write the formula followed by -ide

eg. NaCl sodium chloride eg. calcium phosphide

Mg3N2 magnesium nitride Ca2+ P3-

Ca3P2

2. Polyatomic Ions


- write the name of the negative ion - cross over the charges to write the formula

eg. CaSO4 calcium sulfate eg. magnesium nitrate

Al(OH)3 aluminum hydroxide Mg2+ NO3-

Mg(NO3)2

3. MultiValent Metals- use Roman Numerals to indicate the ion charge(Stock System)

OR

- use the suffix -ic to indicate the smaller ion charge or -ous for the larger ion charge.

Names Formulaseg. CoCl2 - cobalt(II) chloride eg. nickel(II) nitride

- cobaltous chloride Ni2+ N3- (cross over)CoCl3 - cobalt(III) chloride

- cobaltic chloride Ni3N2

NOTE: After crossing over the charges to get the formula, make sure you are using thesimplest ratio between the ions.eg. magnesium oxide - Mg2O2 becomes MgO

DON’T USE PREFIXES FOR IONIC COMPOUNDS.

1. Simple Ions


- write the name of the negative ion - cross over the charges to write the formula followed by -ide

eg. NaCl sodium chloride eg. calcium phosphide

Mg3N2 magnesium nitride Ca2+ P3-

Ca3P2

2. Polyatomic Ions


- write the name of the negative ion - cross over the charges to write the formula

eg. CaSO4 calcium sulfate eg. magnesium nitrate

Al(OH)3 aluminum hydroxide Mg2+ NO3-

Mg(NO3)2

3. MultiValent Metals- use Roman Numerals to indicate the ion charge(Stock System)

OR

- use the suffix -ic to indicate the smaller ion charge or -ous for the larger ion charge.

Names Formulaseg. CoCl2 - cobalt(II) chloride eg. nickel(II) nitride

- cobaltous chloride Ni2+ N3- (cross over)CoCl3 - cobalt(III) chloride

- cobaltic chloride Ni3N2

NOTE: After crossing over the charges to get the formula, make sure you are using thesimplest ratio between the ions.eg. magnesium oxide - Mg2O2 becomes MgO

DON’T USE PREFIXES FOR IONIC COMPOUNDS.

Hydrated ionic compounds have WATER attached to their crystal lattice structure.

Solutions become hydrated when they are crystallized from a water solution.

They are often recognizable by eye because they are often SHINY and TRANSLUCENT.

Examples: ◦ Bluestone, Epsom salts, Rock salts

BLUESTONE CuSO4 ∙5H2O◦ 5 H2O molecules attached to each CuSO4

compound.◦ The “dot” represents a weak bond.

HYDRATED IONIC COMPOUNDS

We indicate the presence of water with the word HYDRATE and we indicate the number of water molecules with our GREEK PREFIXES:

MONO 1, DI 2, TRI 3, TETRA 4, PENTA 5, HEXA 6, HEPTA 7, OCTA 8, NONA 9, DECA 10

ANHYDROUS: NO water attached

HYDRATED IONIC COMPOUNDS

barium chloride dihydrate _____________________

potassium hydroxide hexahydrate _____________________


sodium carbonate octahydrate _____________________

cobalt (II) chloride decahydrate _____________________


CaSO4 ∙2H2O _____________________

Na3PO4 ∙4H2O ______________________


HCN ∙ 3H2O _____________________

HOMEWORK:◦ DO THE SHEET ON HYDRATED IONIC COMPOUNDS

ON THE NEXT PAGE OF YOUR HANDOUT.


multivalent ionic compounds

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