Binary Compounds with Multiple Charge Cations

Multiple Charge Cations Some metals form CATIONS with MORE THAN ONE POSSIBLE CHARGE. Metals from the TRANSITION METALS Some HEAVY ATOMIC MASS NUMBER elements. The elements are referred to as MULTIPLE OXIDATION STATE elements. Only METALS form these ions…there are NO ANIONS (- ions) with multiple charges!

In the NAMES of compounds, these elements are identified by a ROMAN NUMERAL INSIDE A PARENTHESIS following the name of the CATION ELEMENT. For example Iron (III) Oxide indicated that Iron is a MULTIPLE CHARGE CATION.

WRITING FORMULAS with Multiple Charge Cations The ROMAN NUMERAL in the formula’s name actually makes it a little easier to WRITE A FORMULA. The purpose of the ROMAN NUMERAL is to indicate the POSITIVE CHARGE of the cation in this particular compound. For Example Iron (III) Oxide indicates that Iron has a +3 CHARGE in this compound.

changed to -ide)…always get the negative charge Practice Problem Write the formula for Iron (III) Oxide. Iron (III) Oxide +3 Oxide = Oxygen (ending changed to -ide)…always get the negative charge from the Periodic Table.

[ +3 ] + [ -2 ] Fe O Fe O Fe2O3 2 3 2 3

More Practice What would be the formula for Lead (IV) Nitride? 1. Look at list to see if you have a cation with more than one charge. 2. Write symbols for both ions and assign charge. 3. Balance charges and write the formula.