Naming Ionic Compounds
• Name the positive ion first by writing the
f ll name off the
full
th metallic
t lli element.
l
t
• Name the non-metal ion next by dropping
the last syllable(s) of the name of the
element and adding the suffix “ide.”
Naming Examples
• Sodium and chlorine combine to become
– Sodium chloride
• Mg and O
– Magnesium oxide
• HF
– Hydrogen fluoride
1
The Stock System
• Used for elements that can have more
th one cation.
than
ti
– Fe2+ - Iron(II); Fe3+ - Iron(III)
– Cu+ - Copper(I); Cu2+ - Copper(II)
Polyatomic Ions
• There are some special groups of atoms
off more than
th one element.
l
t
– OH- (hydroxide)
– NH4+ (ammonium)
– NO3- (nitrate)
– SO4- (sulfate)
2
Writing Chemical Formulas for
Ionic Compounds
• Write the chemical ssymbol
mbol for both ions
(including the charge)
• “Cross-over” the charge numbers ignoring
the signs
• Simplify if possible
Aluminum Oxide
Al 3+ O 2-
• Write the chemical symbol for both ions
(including the charge)
3
2Al 3+
O
2
3
• “Cross-over” the charge numbers ignoring
the signs
Al 2 O 3
• Simplify if possible
4
Iron(II) Oxide
Fe2+ O 2-
• Write the chemical symbol for both ions
(including the charge)
2Fe 2+
O
2
2
• “Cross-over” the charge numbers ignoring
the signs
5
Fe2 O 2
Fe O
• Simplify if possible
Examples
• Magnesium Fluoride
– MgF2
• Sodium Oxide
– Na2O
• Copper(II) Oxide
– CuO
C O
6
Naming Binary Molecular
Compounds
• The first non-metal name is written in full.
• The second non-metal element is named
with the suffix “ide” ending.
• Assign a prefix to each element
expressing the number of atoms present in
the molecule.
molecule
Prefixes
• Mono=1 (only used with the second
element)
l
t)
• Di = 2
• Tri = 3
• Tetra = 4
• Penta = 5
• Hexa = 6
7
Examples
• CO2
– Carbon dioxide
• N 2O 5
– Dinitrogen pentoxide
Writing Chemical Formulas for
Binary Molecular Compounds
• Write the chemical ssymbol
mbol for both
elements
• Write the number indicated by the prefix
8
Tricarbon tetrahydride
C
H
• Write the chemical symbol for both
elements
C3 H4
• Write the number indicated by the prefix
9
Examples
• Nitrogen monoxide
– NO
• Sulfur trioxide
– SO3
• Carbon tetrachloride
– CCl4
• Dicarbon Hexahydride
– C2H6
10