Ionic Nomenclature Ionic Nomenclature Multi-valent metals

What does What does multivalentmultivalent mean? mean?Some transition metals are multivalent

This means they have more than one ion form

Look at the periodic table and locate some multivalent transition metals

What are multivalent ions?

For Example: Copper has 2 ion forms Can be a 1+ or 2+ ion

Copper I Chloride Copper II Chloride

Writing names for Writing names for multivalentmultivalent ionsionsWe need to distinguish between the two or

three different ion formsUse roman numerals from I – VII which

corresponds to 1+ - 7+ ion charges

Metal Ion charge Roman Numeral1+ I2+ II3+ III4+ IV5+ V6+ VI7+ VII

Writing formulas for compounds Writing formulas for compounds containing a multivalent metalcontaining a multivalent metalFor example:

◦Nickel can have two ion forms, Ni2+ and Ni3+

◦These are named nickel (II) and Nickel (III)

There will only be 1 multivalent metal in a compound

It is the metal so it is first in the name (same as ionic compounds)

The roman numeral will indicate which ion form is in the compound

Steps for writing formulas for Steps for writing formulas for multivalent compoundsmultivalent compounds

Step 1: Identify each ion and its charge

Step 2: Determine the total charges needed to balance positive and negative

Step 3: Note the ratio of positive ions to negative ions

Step 4: Use subscripts to write the formula, 1’s are not shown in subscript

Try the formula for Try the formula for titanium (IV) fluoridetitanium (IV) fluoride

189-191

Ti4+ and F1-

+4 = -1-1-1-1

ions

Total charge to balance

ratio 1 : 4

formula TiF4

Criss-cross rule: Criss-cross rule: A useful trickA useful trick

Mn3+ and S2-

+3+3 = -2-2-2

ions

Total charge to balance

ratio 2 : 3

formula Mn2S3

Manganese (III) Sulfide

The 3 on the Mn ion becomes the # of S ions

Writing formulas for compounds Writing formulas for compounds that contain a that contain a multivalentmultivalent metal metal

Key Points:The metal is always firstThe metal is always the positive ion

The metal could be a multivalent metal

Go to the periodic table and check

Now try these:Now try these:

a. Iron (II) oxide

b. Iron (III) oxide

c. Copper (II) nitride

d. Lead (IV) sulfide

a. FeO

b. Fe2O3

c. Cu3N2

d. PbS2

Steps for Writing formulas for compounds Steps for Writing formulas for compounds that contain a that contain a multivalentmultivalent metal metal

Step 1: Identify a multivalent metal

Step 2: identify its different ion forms

Step 3: determine the ratio of ions in the formula

Step 4: what is the charge on the negative ion?

Step 5: Balance the positive and negative charges

Step 6: Write the name using roman numerals in brackets, following the positive ion to indicate which ion was used

Example: FeIExample: FeI22 Is there a multivalent metal?

Yes, Fe, Iron What are its different ion forms?

3+ and 2+ What is the ratio of ions

1 Fe : 2 I What is the charge on the negative ion

I, Iodine, ion charge is 1- but there are 2 so the total negative charge is 2-

Balance the positive and negative charges Iron must have a 2+ charge to balance the two 1- charges from Iodine

Write the name using a roman numeral to say which ion form of Iron is present

The negative ion must drop its ending and add –ide (same as ionic compounds)

Iron (II) Iodide

Try another example: PbFTry another example: PbF44

Pb 2+ and 4+Pb 1: 4 FF’s ion charge 1-Balance the charges

4+ charges to balance the 4 1- charges of FTherefore Pb must be the 4+ ionLead (IV) Fluoride

Names with Multivalent IonsNames with Multivalent Ions

Try it with copper:

CuCl2

CuSO4

Cu2O

CuO

Copper (II) chloride

Copper (II) sulphate

Copper (I) oxide

Copper (II) oxide