3.2 Names and Formulas of Ionic Compounds

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INCR

EASI

NG

REA

CTIV

ITY

Naming Simple Ionic Compounds Rules for naming simple ionic Rules for naming simple ionic

compounds:compounds:

1.1. Write the name of the Write the name of the metal metal (positive ion) first.(positive ion) first.

2.2. Write the name of the Write the name of the non-metal non-metal (negative ion) second.(negative ion) second.

3.3. Change the ending of the non-metal Change the ending of the non-metal ion to ion to “ide.”“ide.”

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Naming Simple Ionic Compounds Examples:• Li3N __________________________

• MgBr2 __________________________

• Ag2O __________________________

• CdS __________________________

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Naming Simple Ionic Compounds

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Writing Formulas for Simple Ionic Compounds Rules for writing formulas for ionic Rules for writing formulas for ionic

compounds:compounds:1.1. STEP ONE: Write the STEP ONE: Write the symbolsymbol for the more for the more

metallic element firstmetallic element first. Then, write the . Then, write the symbol for the non-metallic element. symbol for the non-metallic element.

2.2. STEP TWO: Write the STEP TWO: Write the combining capacitiescombining capacities for the elements. Ignore the for the elements. Ignore the + and – + and – charges.charges. *If there is *If there is no #no #, the combining , the combining capacity is capacity is 11. .

3.3. STEP THREE: STEP THREE: Swap and drop Swap and drop the combining the combining capacities to get the subscripts.capacities to get the subscripts.

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Writing Formulas for Simple Ionic Compounds Examples:• Barium phosphide ______________

• Aluminum nitride ______________• Zinc oxide ______________• Rubidium bromide ______________

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Multivalent Metal Compounds Many metals are multivalent, meaning the

metals form two or more different positive ions with different charges.

For example, the atom iron forms two ions Fe2+ and Fe3+.

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Multivalent Metal Compounds To distinguish different ions for the same metal,

roman numerals are added to their name. For example, Fe3+ would be named “iron(III)”

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Writing Formulas for Ionic Compounds Containing Multivalent Metals

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It is easyeasy to write the formulas write the formulas for multivalent ionic compounds, because they tell you their combining capacities tell you their combining capacities so you don’t need to look on the periodic table.

Writing Formulas for Ionic Compounds Containing Multivalent Metals Examples:• Iron (II) phosphide ______________• Manganese (II) oxide ______________• Tin (II) sulfide ______________• Lead (IV) chloride ______________

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Naming Ionic Compounds Containing Multivalent MetalsIt is a little more difficult to name more difficult to name a multivalent ionic compound, because you have to work backwards work backwards to figure out which combining capacity was used. Remember to use a ROMAN NUMERALROMAN NUMERAL!!!

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Naming Ionic Compounds Containing Multivalent Metals Examples:• Fe2O3 __________________________

• PbF4 __________________________

• MnS __________________________• TiS2 __________________________

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Naming Ionic Compounds Containing Polyatomic IonsWhen you are naming compounds with more than more than two elementstwo elements, you are dealing with a polyatomic polyatomic ionion. All you need to do, is findfind it in the chart so you can name your compound.1.If the polyatomic ion group has a positive charge positive charge (+) it acts like a metalmetal and comes firstcomes first in the name.2.If the polyatomic ion group has a negative charge (-) it acts like a non-metal non-metal and comes secondsecond in the name.

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Naming Ionic Compounds Containing Polyatomic Ions Examples:• Fe(OH)3

________________________• Mg3(PO4)2 ________________________

• (NH4)3P ________________________

• Ca(CH3COO)2 ________________________

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Writing Formulas for Ionic Compounds Containing Polyatomic IonsEach polyatomic ion has its own has its own combining capacity combining capacity that should be used when writing a chemical formula.

USE BRACKETS AROUND THE POLYATOMIC USE BRACKETS AROUND THE POLYATOMIC IONSIONS!!

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Writing Formulas for Ionic Compounds Containing Polyatomic Ions Examples:• Sodium chromate ________________• Ammonium nitrate

________________• Lead (II) perchlorate

________________• Tin (II) cyanide

________________

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See page 91Section 3.2 Quiz