Chapter 7 Naming Compounds

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Chapter 7 NamingCompounds
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Binary Ionic Compounds

• A binary compound is one made of two different
  elements.
• There can be one of each element such as in NaCl
  or KF. There can also be several of each element
  such as Na2O or AlBr3.
• remember that all elements involved have ONLY ONE
  charge.

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Points to remember about naming a compound from
its formula

• The order for names in a binary compound is first
  the cation (positive), then the anion (negative).
  
• Cations use the same name that appears in the
  periodic table
• The name of the anion will be made from the root
  of the element's name plus the suffix "-ide."

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Write the name of the following formula H2S

• Step 1 - Look at first element and name it.
  Result of this step hydrogen.
• Step 2 - Look at second element. Use root of its
  full name ( which is sulf-) plus the ending
  "-ide." Result of this step sulfide.
• Hydrogen Sulfide
• Notice that the
• presence of the
• subscript is ignored.

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Write the name of the following formula NaCl

• Step 1 - Look at first element and name it.
  Result of this step sodium.
• Step 2 - Look at second element. Use root of its
  full name ( which is chlor-) plus the ending
  "-ide." Result of this step chloride.
• Sodium Chloride

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Write the name of the following formula MgBr2

• Step 1 - Look at first element and name it.
  Result of this step magnesium.
• Step 2 - Look at second element. Use root of its
  full name ( which is brom-) plus the ending
  "-ide." Result of this step bromide.
• Magnesium Bromide

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Write the name of the following formula KCl

• The first part of the name comes from the first
  element symbol potassium.
• The second part of the name comes from the root
  of the second symbol plus '-ide,' therefore chlor
  ide chloride.
• potassium chloride

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Practice Given the formula write the name

• MgS
• KBr
• Ba3N2
• NaI
• SrF2
• Li2S
• RaCl2

• Magnesium Sulfide
• Potassium Bromide
• Barium Nitride
• Sodium Iodide
• Strontium Fluoride
• Lithium Sulfide
• Radium Chloride

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Given the name write the formula

• If you can say NaCl is Sodium Chloride, now you
  have to say Sodium Chloride is NaCl
• First we learn the criss cross method
• Generally
• the total positive charges must equal the total
  negative charges.
• you cannot change the charges given to you.
• Adjust the subscripts to equalize the charges.

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What is the formula for sodium chloride?
              Write down the Na and Cl right
next to each other, as in this image Move the
positive charge (dropping the sign) to the
subscript position of the anion Move the
negative charge (dropping the sign) to the
subscript position of the cation The result of
all this moving is    Since subscripts of one
are not written, but understood to be present,
the final answer
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Write the formula for magnesium chloride.
              Write down the Mg2 and Cl right
next to each other, as in this image Move the
positive charge (dropping the sign) to the
subscript position of the anion Move the
negative charge (dropping the sign) to the
subscript position of the cation          The
result of all this moving is Since subscripts
of one are not written, but understood to be
present, the final answer
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Write the formula for aluminum oxide.
              Write down the Al3 and O2 right
next to each other, as in this image Move the
positive charge (dropping the sign) to the
subscript position of the anion Move the
negative charge (dropping the sign) to the
subscript position of the cation The result of
all this moving isNotice that there is no fifth
image in this problem. The Al2O3 is at a minimum
set of subscripts, so no reducing is necessary.
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Write the formula for barium oxide.
              Write down the Ba2 and O2 right
next to each other, as in this image             
  Move the positive charge (dropping the sign)
to the subscript position of the
anion               Move the negative charge
(dropping the sign) to the subscript position of
the cation               The result of all this
moving is Since both subscripts have a common
factor of two, we can reduce. After reducing, the
final answer
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Other practice problems

• Solutions
• NaBr
• KCl
• BaI2
• AlCl3
• MgO
• Al2O3

• Given the name write the formula
• sodium bromide
• potassium chloride
• barium iodide
• aluminum chloride
• magnesium oxide
• aluminum oxide

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Transition metals can have more than one charge

• In nature Iron can be found as Fe2 or Fe3
• The two form different chemicals with different
  properties
• Originally two forms of the Latin name for Iron
  (Ferrum) were used
• Fe2 was called Ferrous
• Fe3 was called Ferric
• ous less charge
• ic more charge

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Ferric vs. Ferrous
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Another example

• In nature Lead can be found as Pb2 or Pb4
• The two form different chemicals with different
  properties
• Originally two forms of the Latin name for Lead
  (Plumbum) were used
• Pb2 was called Plumbous
• Pb4 was called Plumbic
• ous less charge
• ic more charge

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What is the charge of the ion typically formed
by each element?

• Sulfur
• Lead, 4 e- lost
• Strontium
• Argon
• Bromine

• 6. Copper, 1 e- lost
• 7. Selenium
• 8. Barium
• 9. Cesium
• 10. Phosphorus

Solution Plan Find the element on the periodic
table. The group its in determines its charge.
Except transition metals. They might have more
than one kind of charge, so check how many
electrons they lose.
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Solution

• Sulfur S2-
• Sulfide ion
• Lead, 4 e- lost Pb4
• Lead (IV) ion
• Plumbic ion
• Strontium Sr2
• Strontium ion
• Argon
• No ion
• Bromine Br
• Bromide ion

• 6. Copper, 1 e- lost Cu
• Copper (I) ion
• Cuprous ion
• 7. Selenium Se2-
• Selenide ion
• 8. Barium Ba2
• Barium ion
• 9. Cesium Cs
• Cesium ion
• 10. Phosphorus P3-
• Phosphide ion

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Polyatomic ions

• O2-, Fe2, Fe3, Li are all monatomic ions
• They only contain one type of ion
• Some groups of atoms stick together and all
  together have one charge
• Like a family
• These are polyatomic ions
• Most end in ate or ite
• Ammonium, cyanide, hydroxide are exceptions to
  the ate or ite rule

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Example

• Sulfate/Sulfite
• SO42- / SO32-
• The ite ending indicates one less oxygen than the
  ate ending
• But it doesnt tell how many Oxygens there are
• NO2- / NO3- nitrate/nitrate

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If the brain slugs havent got you then go
practice.