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What are they? |
How are they named? | If we
know the formula | If we know the name
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Examples | Exercises |
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What are they?
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They are ternary compounds
containing a metallic element, and many groups OH-(hydroxide) as the
oxidation number of the metal. They are
ionic compounds formed by metal cations and anions OH-.
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How are they named?
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Stock´s nomenclature: it is formed by two words. The first
word is the name of the metal, followed immediately by the oxidation number
between brackets and in Roman numbers. If the oxidation number of the metal is
invariable, it is not indicated. The second word is "hydroxide"
METAL(N) hydroxide
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If we know the formula
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In the formula: the oxidation number of the metal is equal to the number
of ions OH–.
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If we know the name
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In the name: Remember that you must know the symbols
of the elements and the oxidation numbers which are invariable.
1. Write the symbol of the first element.
2. Write the group OH.
3. The number of OH matches up with the oxidation number of metal.
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Examples
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| LiOH |
Lithium
hydroxide |
| Ba(OH)2 |
Barium
hydroxide |
| Fe(OH)3 |
Iron(III)
hydroxide |
| Cr(OH)3 |
Chromium(III)
hydroxide |
| Al(OH)3 |
Aluminium
hydroxide |
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Exercises
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In Formulae you have an exercise to write the names of these substances
and to check your results. You also have the answer to the exercise.
In Names you have an exercise to write the formulae for these substances
and to check your results. You have to introduce the formulae without
subscripts, for example for water = H2O. You also have the answer to the
exercise.
   
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