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Nomenclaturewriting chemical formulas

naming chemical compounds

Chapter 7

potassium chromate potassium dichromate

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Sodium and Chlorine

NaClSodium Chloride• Cation 1st: name of element• Anion 2nd: root and add -ide

• When combined together✓ Metals lose e- (+ ion = cation)✓ Nonmetals gain e- (- ion = anion)✓ Ionic Compounds (Type I Binary Ionic)

1A 2A 8A

3A 4A 5A 6A 7A

1+ 1B 2B 3B 4B 5B 6B 7B 8B 9B 10B 1-

Na+ Cl-Na Cl

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Magnesium and Fluorine

MgF2

• The number of electrons lost must equal the number of electrons gained

• The total + and - charge must add to 0

Magnesium Fluoride

1A 2A 8A

3A 4A 5A 6A 7A

1-

2+ 1B 2B 3B 4B 5B 6B 7B 8B 9B 10B

Mg F

Mg2+ F-

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Aluminum and Oxygen

Al2O3

Aluminum Oxide• The number of electrons lost must equal the number

of electrons gained• Overall charge = 0

1A 2A 8A

3A 4A 5A 6A 7A

2-

+ 1B 2B 3B 4B 5B 6B 7B 8B 9B 10B 3+

Al O

Al3+ O2-

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Write the chemical formula for strontium sulfide

SrS• You might have criss-crossed to Sr2S2

but then you must reduce it to the lowest whole number ratio.

• remember always write ionic formula in lowest whole number ratio

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Write the chemical formula for potassium nitride

K3N• K+1N-3

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1A 2A 8A

3A 4A 5A 6A 7A

N O F

Na Mg 1B 2B 3B 4B 5B 6B 7B 8B 9B 10B Al P S Cl

K Ca

The Periodic Table

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Write the chemical formula for gallium oxide

• Ga+3O-2

Ga2O3

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Write the chemical formula for potassium sulfide

• K+1S-2

K2S

Write the chemical name for CaBr2

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Calcium Bromide

Remember:• the metal (cation is 1st)• the nonmetal (anion is 2nd : root and -ide)

Chemical formula for copper fluoride

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1A 2A 8A

3A 4A 5A 6A 7A

1B 2B 3B 4B 5B 6B 7B 8B 9B 10B

2+1+ 2+

Oxidation states for Copper:

1+: Cu(I) 2+: Cu(II)

Roman Numerals refresh1: I2: II3: III4: IV5: V6: VI7: VII

Know F- • The number of electrons lost = the number of electrons gained• Overall charge = 0• so use Cu+ or Cu(I)

• CuF

Chemical formula for copper(II) fluoride

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Copper: F- 1+: Cu(I) 2+: Cu(II)

CuF2

Roman numeral tells you the charge on copper Cu(II) = Cu2+

1A 2A 8A

3A 4A 5A 6A 7A

1B 2B 3B 4B 5B 6B 7B 8B 9B 10B

2+1+ 2+

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Write the chemical formula for zinc chloride

ZnCl2

• Remember that zinc is one of the transition metals that does not require a Roman #, since it’s oxidation state is always +2.

1A 2A 8A

3A 4A 5A 6A 7A

1B 2B 3B 4B 5B 6B 7B 8B 9B 10B

2+1+ 2+

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Write the chemical formula for chromium (VI) sulfide

• The Roman # tells you the +6 charge on the chromium metal

• Cr+6S-2

• You might have criss-crossed to Cr2S6 but then you must reduce it to the lowest whole number ratio.

• CrS3

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Write the name for Fe2O3

• you can un-criss-cross• or you can determine the charge on iron

by working from the charge on the anion• iron(III) oxide

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Write the name for Ag2S

• No need for a Roman # since silver is always

+1(memorize along

with Zn and Cd)

Silver sulfide

1A 2A 8A

3A 4A 5A 6A 7A

1B 2B 3B 4B 5B 6B 7B 8B 9B 10B

2+

1+ 2+

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Write the name for Cu2O• You can “un-criss-cross”• or you can work into the cation by

knowing that the anion is -2✓ The total + and - charge must add to 0✓ this means that electrons lost = electrons gained✓ the Roman # = the individual oxidation state of one of

the metal ions (not the total metal charge)

• Copper (I) oxide

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Write the name for CrP2

• you can’t just un-criss-cross because this is a formula which has been reduced.

✓ work off the non-metal’s charge✓ remember the total + must equal - that

means the e- lost = e- gained

chromium (VI) phosphide

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Roadmap for Naming Binary Compounds