Binary Compounds with Multiple Charge Cations Multiple Charge

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.

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

• • 2 [ +3 ] + 3 [ -2 ] Fe O Fe 2 O 3 Fe 2 O 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.