IONIC COMPOUNDS

Naming and Formula Writing

 OBJECTIVES: 

Apply the rules for

naming and writing formulas

for binary ionic compounds.



Apply the rules for

naming and writing formulas

for compounds containing polyatomic ions.

Predicting Charges on Monatomic Ions KNOW THESE !!!!

+1 +2 -3 -2 -1 0 Cd +2

Naming Positive Ions

      Before you name an Ion you have to know the charge.

Group 1 = always +1 Group 2 = always +2 Aluminum = always +3 Zinc and Cadmium = always +2 Silver = always +1

The Other Metals

 All other metals can have various positive charges from +1 to +7  Roman Numerals are used to tell the charge

Monatomic Ions

Naming Postive Ions

 With group 1, 2, Al, Zn, Cd, and Ag you just give the name of the atom     Na + is Sodium Mg +2 is Magnesium Ag Al + +3 is Silver is Aluminum

All the other metals

 With all other metals you give the name Metal followed by a

roman numeral

     Cu + - Copper (I) Cu +2 – Copper (II) Fe +2 – Iron (II) Fe +3 – Iron (III) U +6 – Uranium (VI)

Naming negative ions

     All negative ions have their endings changed to –ide Oxygen becomes oxide Fluorine becomes Fluoride Nitrogen becomes Nitride Chlorine becomes Chloride

Names of other Negative Ions

      Carbide = what you want your parents to do for you Boride = what happened at the rodeo Silicide = what you are seeing right now Fluoride = a state in the union Iodide = Very sad, I guess we will have to Barium.

Telleride = Telling the driver where you want to go

Formulas of Ionic Compounds Formulas of ionic compounds are determined from the charges on the ions Na



atoms +

  

F :

  

ions

 

– Na + : F :

  

NaF sodium + fluorine sodium fluoride formula Charge balance: 1+ 1 = 0

Writing a Formula Write the formula for the ionic compound that will form between Ba 2+ and Cl



.

To cancel out Ba’s +2, then two -1 Cl’s are needed.

Solution: 1. Balance charge with + and – ions 2. Write the positive ion of metal first, and the negative ion Ba 2+ Cl



Cl



3. Write the number of ions needed as subscripts BaCl 2

Balancing a formula by math

 Every ionic compound should have a formula that has a charge that equals zero.

 Barium Fluoride     Ba +2 Two F How many F’s are needed to balance Ba +2 Formula is BaF 2 ?

Another way – Drop, Swap, Reduce

       Aluminum Oxide Al is always +3 Oxide is always -2 Al +3 , O -2 DROP: Al 3 O 2 SWAP: Al 2 O 3 REDUCE: 2 and 3 are lowest integers, so leave alone

Another example

       Magnesium Oxide Mg is +2 Oxide is -2 Mg +2 , O -2 DROP: Mg 2 O 2 SWAP: Mg 2 O 2 REDUCE: MgO, 2 and 2 divide each other out.

 Barium phosphide  Barium will form Ba 2+  Phosphorus will form P 3  Formula is

Ba 3 P 2

 Sodium sulfide  Sodium will form Na +  Sulfur will form S 2  Formula is

Na 2 S

 Calcium chloride  Calcium will form Ca 2+  Chlorine will form Cl 1  Formula is

CaCl 2

Complete in your journal

Learning Check Write the correct formula for the compounds containing the following ions: 1. Na + , S 2 a) NaS 2. Al 3+ , Cl b) Na 2 S c) NaS 2 a) AlCl 3 3. Mg 2+ , N 3 a) MgN b) AlCl b) Mg 2 N 3 c) Al 3 Cl c) Mg 3 N 2

Naming Compounds Binary Ionic Compounds:



1. Cation first, then anion



2. Monatomic cation = name of the element



Ca 2+ = calcium ion



3. Monatomic anion = root



Cl



= chlor ide



CaCl 2 = + calcium chlor -ide ide

Naming Binary Ionic Compounds



Examples: NaCl



sodium chloride ZnI 2 Al 2 O 3



zinc iodide



aluminum oxide

Complete in your journal

Learning Check Complete the names of the following binary compounds: Na 3 N sodium ________________ KBr potassium ________________ Al 2 O 3 MgS aluminum ________________ _________________________

Transition Metals Elements that can have more than one possible charge MUST have a Roman Numeral to indicate the charge on the individual ion.

1+ or 2+ 2+ or 3+ Cu + , Cu 2+ Fe 2+ , Fe 3+ copper(I) ion iron(II) ion copper (II) ion iron(III) ion

Names of Variable Ions These elements REQUIRE Roman Numerals because they can have more than one possible charge: anything except Group 1A, 2A, Ag, Zn, Cd, and Al (You should already know the charges on these!) Or another way to say it is: Transition metals and the metals in groups 4A and 5A (except Ag, Zn, Cd, and Al) require a Roman Numeral.

FeCl CuCl SnF 4 PbCl 2 Fe 2 S 3 3 (Fe 3+ ) iron (III) chloride (Cu + ) copper (I) chloride (Sn 4+ ) tin (IV) fluoride (Pb 2+ ) lead (II) chloride (Fe 3+ ) iron (III) sulfide

Examples of Older Names of Cations formed from Transition Metals (you do not have to memorize these)

Complete in your journal

Learning Check Complete the names of the following binary compounds with variable metal ions: FeBr CuCl 2 iron (_____) bromide copper (_____) chloride SnO 2 Fe 2 O 3 Hg 2 S ___(_____ ) ______________ ________________________ ________________________

Polyatomic Ions

 Some ions are composed of more then one atom.

 These are called polyatomic ions  Poly = more

Formulas and names

    Nitrate = NO 3 Sulfate = SO 4 -2 Silver nitrate   Ag + NO 3 DSR = AgNO 3 Copper (I) Sulfate   Cu + SO 4 -2 Cu 2 SO 4

More Polyatomics

  Lead (IV) Phosphate   Pb +4 PO 4 -3 Pb 3 (PO 4 ) 4 Notice: When more then one Polyatomic is present you surround it with ()  Big: The subscripts on Polyatomic ions are NEVER changed.

Complete in your journal

Learning Check Write the correct formula for the compounds containing the following ions: 1. Na + , PO 4 -3 a) Na PO 4 2. Al 3+ , NO 3 a) Al( NO 3 ) 3 3. NH 4 + , N 3 a) NH 4 N b) Na b) Al b) NH 2 PO NO 4 N 3 4 c) Na c) Al c) ( 3 3 NH NO 4 PO ) 3 3 4 N

Polyatomic Ions you have to know

NAME FORMULA Acetate Carbonate Chlorate Cyanide Hydroxide C 2 H 3 O -1 CO 3 -2 ClO 3 -1 CN -1 OH -1 Nitrate Peroxide Phosphate Sulfate Ammonium NO 3 -1 O 2 -2 PO 4 -3 SO 4 -2 NH 4 +1

More on Polyatomics

     Most polyatomic ions end in –

ate

. The ending –

ite

means one less oxygen is present then in the ending –

ate

.

Example: Nitr

ate

NO 3 versus Nitr changed, not the charge.

NO

ite

2 : NOTICE: Only the number of O’s

Even More

        The Prefix

Hypo

means two less oxygen’s are present then in –

ate

.

Example:

Hypo

sulfite: SO 2 -2 The Prefix

Per

- means one extra oxygen is present then in –

ate

.

Examples:

Per

chlorate Chlorate Chlor

ite

HypoChlorite

ClO 4 ClO 3 ClO 2 ClO -

What if Hydrogen is in it?

    The Prefix

Bi

means that a Hydrogen is added, and the charge is reduced by one.

Example:

Bi

Carbonate HCO 3 -1 May also go by Hydrogen Carbonate.

Practice by writing the formula or name as required…

 Iron (II) Phosphate  Stannous Fluoride  Potassium Sulfide  Ammonium Chromate  MgSO

4

 FeCl

3

Complete in your journal

Learning Check Match each set with the correct name: A.

Na 2 CO MgSO 3 MgSO 4 3 1) magnesium sulfite 2) magnesium sulfate 3) sodium carbonate B.

Ca(HCO 3 ) 2 1) calcium carbonate CaCO 3 2) calcium phosphate Ca 3 (PO 4 ) 2 3) calcium bicarbonate

Complete in your journal

Learning Check A. aluminum nitrate 1) AlNO 3 2) Al(NO) 3 B. copper(II) nitrate 3) Al(NO 3 ) 3 1) CuNO 3 2) Cu(NO 3 ) 2 C. Iron (III) hydroxide 3) Cu 2 (NO 3 ) 1) FeOH 2) Fe 3 OH D. Tin(IV) hydroxide 3) Fe(OH) 3 1) Sn(OH) 4 2) Sn(OH) 2 3) Sn 4 (OH)

Complete in your journal

Things to look for:

1) If cations have ( ), the number in parenthesis is their charge.

2) 3) If anions end in -ide they are probably off the periodic table (Monoatomic) If anion ends in -ate or –ite , then it is polyatomic

Write the opposite of what is shown; If name shown, write formula; If formula shown, write name.

1. aluminum sulfide 11. Na 2 S 2. barium arsenate 3. copper (I) nitride 12. K 2 SO 13. LiF 4 4. ammonium phosphate 5. lead (IV) nitrate 6. lithium oxalate 7. calcium bicarbonate 8. silver permanganate 9. mercury (I) bromide 10.chromium (III) sulfite 14. Zn(NO 3 ) 2 15. FeCl 3 16. CaCO 3 17. AlBr 3 18. Mg(NO 3 ) 2 19. FeSO 4 20. Pb(NO 3 ) 2