Name Binary Compounds and with Binary Compounds with

Name Binary Compounds and with Binary Compounds with Multiple Charge Cations

• I CAN name a basic binary compound from its empirical formula and also determine the formula/write names for compounds containing multiple charge cations.

Naming a Binary Ionic Compound • What would be the formula for a binary ionic compound of Aluminum and Fluorine? What would the name of this compound be?

1. Determine the Empirical Formula • A) Use the criss-cross method: (+3) Al + Al. F 3 (-1) F = 0

2. Name the Binary Ionic Compound • To name a BINARY IONIC COMPOUND, follow these steps: • 1. Name the CATION by its elemental name. • 2. Name the ANION by its elemental name EXCEPT change its ending to IDE. • a) if the anion ends in “ine” drop and add “ide”. • b) if the anion ends in something other than ine, you USUALLY drop the last syllable then add IDE.

• Some Examples of anions that do not end in INE and will drop the last syllable before adding IDE. Anion Sulfur Oxygen Phosphorus Nitrogen Arsenic Selenium Polonium Antimony Bismuth Becomes in a compound Sulfide Oxide Phosphide Nitride Arsenide Selenide Polonide Antimonide Bismide

PRACTICE PROBLEMS • NAME these binary ionic compounds: • 1. Mg. I 2 2. Ca. S • Magnesium Iodide Calcium Sulfide • 3. Ba. O 4. Ca. At 2 • Barium Oxide Calcium Astatide • 5. K 2 P 6. Al. Cl 3 • Potassium Phosphide Aluminum Chloride

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!

**Some Common Multiple Oxidation Elements**

INDICATING THE PRESENCE OF A MULTIPLE CHARGE CATION. • 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 • Indicates a POSITIVE cation charge Iron (III) Oxide = Oxygen (ending changed to -ide)…always get the negative charge from the Periodic Table.

• • (+3 ) + (-2 ) = 0 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.

Naming Compounds with Multiple Oxidation Cations • Follow the same rules as for a BINARY IONIC COMPOUND except: • After the name of the multiox cation, place a Roman Numeral in a parenthesis indicating which charge state the ion is in, then add the name of the anion, changing the ending to IDE.

PRATICE PROBLEMS Name these binary ionic compounds containing multiple oxidation cations. 1. Pb. O 2. Sn. F 4 3. Cu. S 4. Fe 3 P 2 5. Cr 2 O 3 6. Hg 2 I 2

EXAMPLE • Take a look at Pb. O. • Look at the cation…can it have more than one oxidation state (charge)? • YES it could be Pb+2 or Pb+4 • Which state is Pb in in this compound? • Look at the ANION…determine the total NEGATIVE charge. • O is -2, and there’s only 1 atom, so the total NEGATIVE charge is -2, therefore the total POSITIVE charge must be +2. • Since there is only one atom of Pb, it must be in the +2 state.

• • • (+2) + (-2) = 0 Pb O Pb 2 O 2 • Can you reduce the subscripts? • YES Pb 2 O 2 Pb. O • Remember an EMPIRICAL FORMULA is the simplest whole number ratio of atoms in the compound.