Chemistry 11 – Unit #1 Nomenclature Binary Compounds with Elements having one valence (charge) value Binary compounds contain two elements only. They are usually ionic compounds When naming compounds the least electronegative element is usually written first. Rules for Binary Compounds The name of the binary compound always ends in "ide" . The first mentioned element uses its name as it appears on the Periodic table Elements have a valence value determined by their group on the Periodic table 1+ 2+ 3+ 4 +/- 3- 2- 1- 0 N.B. see the periodic table for valences of the transitions metals Zero Sum Rule : For neutral chemical formulas containing ions, the sum of the positive and negative ions must equal zero. Cross-over-rule for writing Formulas 1. Write down the symbols of the elements in the order given in the name 2. Write valences above elements symbol 3. Divide valences by the highest common multiple 4. Cross-over valences 5. Drop all 1's and unnecessary brackets Examples:
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Chemistry 11 – Unit #1Nomenclature
Binary Compounds with Elements having one valence (charge) value
Binary compounds contain two elements only. They are usually ionic compounds When naming compounds the least electronegative element is usually written first.
Rules for Binary Compounds
The name of the binary compound always ends in "ide". The first mentioned element uses its name as it appears on the Periodic table Elements have a valence value determined by their group on the Periodic table
1+ 2+ 3+ 4 +/- 3- 2- 1- 0
N.B. see the periodic table for valences of the transitions metals
Zero Sum Rule: For neutral chemical formulas containing ions, the sum of the positive and negative ions must equal zero.
Cross-over-rule for writing Formulas
1. Write down the symbols of the elements in the order given in the name2. Write valences above elements symbol3. Divide valences by the highest common multiple4. Cross-over valences5. Drop all 1's and unnecessary brackets
Examples: sodium oxide Na2O calcium sulfide CaS magnesium bromide MgBr2
Exercise: For all exercises you will give the name if formula provided and the formula if the name is provided.
Binary Compounds with Elements having multiple valence values
Rules for Binary Compounds
The name of the binary compound always ends in "ide".
Whenever the first mentioned element has more than one valence value, this must be indicated in the name. It will always be the first element. The second element has a valence value equal to the value for its group on the periodic table.
Certain valence values of transition metals must be memorized. On the Periodic table, above each symbol are a number of values which the legend calls oxidation states. In many cases these also correspond to valence values.
There are three ways of naming compounds containing elements that can have multiple valences, The different methods must not be mixed.
Method 1 - Roman numeral method (IUPAC)
The valence value to be used is indicated by using uncrossed Roman numerals It is placed in brackets immediately following the name of the first element.
This method does not use the valence values. The Greek prefix is placed in front of the element name to indicate how many atoms of the element to place in the formula. The word "mono" is usually omitted only if it applies to the first element.
Formula of elements: Most elements are written as single entities: Metals (solids in their standard state except mercury) Noble gases Diatomics - H O F Br I N Cl (all are gasses except Br and I)
two other non-metals exceptions: sulphur S(s) & S8(s) ; phosphorus P(s) & P4(s)
Polyatomic ions (Radicals)
Is an ion made up of two or more atoms Some of the following list of polyatomic ions will have to be memorized along with their valences. These polyatomic ions behave as if they were a single entity and follow the cross-over rule in the
same manner as other single elements. Brackets are used in the formula, only if it turns out that there are 2 or more of the polyatomic ion
indicated in the formula: Eg. Brackets are used in Al2(SO4)3 but not in Na3PO4 The only polyatomic cation to be studied is NH4+
The others are polyatomic anions. i.e. they carry a negative charge
See p. 666 to fill in tableradical name formula radical name formulathiocyanate SCN- nitrate
Greek prefixes are used to indicate how many water molecules are associated with the crystal.Examples: copper(II) sulfate pentahydrate CuSO4.5H2O
chlorine octahydrate Cl2.8H2O
1) calcium sulfate dihydrate __________
2) magnesium sulfite heptahydrate __________
3) sodium carbonate decahydrate _________
4) aluminum oxide monohydrate __________
5) ferric chloride hexahydrate __________
6) calcium nitrate trihydrate __________
7)cadmium bromide tetrahydrate __________
8) chromium(III) nitrate nonahydrate_________
9) barium hydroxide octahydrate __________
10) cobalt(II) perchlorate pentahydrate__________
11) barium chloride dihydrate __________
12) aluminum nitrate monohydrate __________
13) bromine decahydrate __________
14) iodine tetrahydrate __________
15) copper(II) sulfite hexahydrate __________
16) ferrous iodide tetrahydrate __________
17) lithium chloride monohydrate __________
18) beryllium nitrate tetrahydrate __________
Peroxides:These are binary oxides, which contain an extra oxygen atom. (O2
2- = peroxide radical)Rule: 1. Write the formula as if the regular oxide Na2O H2O CaO
2. Add on one extra oxygen atom Na2O2 H2O2 CaO2Do not at this stage cancel any of the subscripts.
1) zinc peroxide ____________________
2) calcium peroxide ____________________
3) cesium peroxide ____________________
4) copper(II) peroxide ____________________
5) magnesium peroxide ____________________
6) potassium peroxide ____________________
7) strontium peroxide ____________________
8) hydrogen peroxide ____________________
9) barium peroxide ____________________
10) aluminum peroxide ____________________
Thio CompoundsThe prefix thio in the name indicates that an oxygen atom has been replaced by a sulphur atom.Examples: potassium sulphate K2SO4 potassium thiosulphate K2S2O3
NOMENCLATURE 4ACIDS:There are three groups of acids: - binary acids
- oxy acids- derived oxy acids
Binary Acids
1. All have the prefix hydro and end with ic. 2. All must contain hydrogen as the first element.3. Use the normal cross-over-rule to determine the formula.4. All are dissociated in water and must be so indicated by using (aq) behind the formula.5. Have no oxygen in their formula
For all exercises you will give the name if formula provided and the formula if the name is provided.
hydrobromic acid ________
hydroiodic acid ________
hydrofluoric acid ________
hydrotelluric acid ________
hydroselenic acid ________
hydrophosphoric acid ________
hydrofluoric acid ________
hydrosulfuric acid ________
Oxy acids
1. All contain H, O and at least one other non-metal element2. The name of the acid ends in ic.3. The name of the associated radical ends in ate.4. The valence value of the associated radical is equal to the number of acidic hydrogen atoms in the acid.
The following six oxy acids and their associated radicals along with their valence values must be memorized:
Name of the Acid Formula of the Acid Name of the
associated radical
Formula of the
associated radical
valence value for the
associated radical
chromic acid H2CrO4 chromate CrO4 2
nitric acid HNO3 nitrate NO3 1
fluoric acid HFO3 fluorate FO3 1
carbonic acid H2CO3 carbonate CO3 2
sulfuric acid H2SO4 sulfate SO4 2
phosphoric acid H3PO4 phosphate PO4 3
NOTE:Using the periodic table it is possible to write the names and formulas for a number of other oxy acids using the fact that members of the same chemical family have similar chemical properties.
Elements of the same chemical family (group) follow the pattern of the oxy acid immediately abovethe oxy acid that has been memorized.
Salts are compounds which can be formed when an acid and a base neutralize each other. Most of the compounds in the section on binary compounds could be considered to be salts fromed
from a base and a binary acid. Salts can also be formed from a base and an oxy acid or derived oxy acid.
Acid Radicals The oxy acids which have more than one acidic hydrogen are able to lose the hydrogens, one at a time. This gives rise to radicals, with acidic hydrogens still attached These radicals are referred to as acid radicals:
* Valence value = Valence of the non-acid radical - # H's still attached.
For the following give the formula and valence value of the radicals listed:
phosphite _____________ ____
monohydrogenphosphite ___________ ____
dihydrogenphosphite _____________ ____
hypophosphite _____________ ____
monohydrogenhypophosphite________ ____
dihydrogenhypophosphite ________ ____
sulphate ________ ____
monohydrogensulphate ________ ____
suphite ________ ____
monohydrogensulphite ________ ____
carbonate ________ ____
monohydrogencarbonate ________ ____
chromate ________ ____
monohydrogechromate ________ ____
Acid Salts:The acid radicals are treated just like any other radical:Examples:
calcium dihydrogenhypophosphite Ca(H2PO2)2
potassium monohydrogen carbonate KHCO3Aluminum hydrogensulphite Al(HSO3)3 Note: mono is understood
Note: In some old texts, the prefix "bi" is sometimes used instead of monohydrogen. Its use is very selective and should not
be considered to name compounds, but know how to write the formulas when the prefix "bi" is used.Examples: sodium bicarbonate NaHCO3 potassium bisulphite KHSO3