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