Naming Compounds
Nomenclature
1
We know that…
•The _____________ valence is
written before the ____________
valence in a chemical formula.
2
And the name is…
• NaCl
• sodium chloride
• AgBr3
• silver bromide
• Al2O3
• aluminum oxide
• BaS
• barium sulfide
• What type of substances are the first
components in each the compounds?
3
Deducing the rules…
• What ‘rule(s)’ are used to name each of the
compounds?
– Name the first element.
– Name the second element, but modify to
have an -ide ending.
– AlBr3
Aluminum Bromide
– BaO
Barium Oxide
4
Now what do we do???
Cu2S
CuS
• Color(s): metallic luster,
dark color usually
charcoal gray or black,
sometimes iridescent
colors
• Density 5.6 g/cm3
• Melting point1130 °C
• Solubility: slightly soluble
in HCl; soluble in
NH4OH; dissolves in
KCN
• Color(s): Indigo blue
(tarnished to purple or
black
• Density 4.6 g/cm3
• Melting point 103 °C
• Solubility: in H2S
5
•Cu2S
CuS
• What is different about the first components in these
compounds that was not the case in the compounds on
the first page?
• If the names are:
• copper I sulfide
and
copper II sulfide
• What is the rule that is used for compounds like this?
6
More than one positive valence…
• If the first element is a metal that has more than
one positive valences…
– Name the first element.
– Indicate the valence number of the metal in
ROMAN NUMERALS
– Name the second element, but modify to have an ide ending.
– MnO
• Manganese II oxide
– SbBr3
• Antimony III bromide
7
What about compounds like
these?
• (NO)
• (NO2)
• (N2O)
• (N2O3)
• (N2O4)
• (N2O5)
• What type of substances are the first
components in each the compounds?
8
If the correct names are…
• (NO), nitrogen monoxide
• (NO2), nitrogen dioxide
• (N2O), dinitrogen monoxide
• (N2O3), dinitrogen trioxide
• (N2O4), dinitrogen tetroxide, or dinitrogen
tetraoxide
• (N2O5), dinitrogen pentoxide, or
dinitrogen penatoxide
What is the rule that is used here?
9
If the first element is a nonmetal
• Use prefixes to indicate the number of
each atom of each element in the
compound.
• Name the first element.
• Name the second element, but modify to
have an -ide ending.
10
PREFIXES
• mono = one (optional on 1st element)
•
•
•
•
di = two
tri = three
tetra = four
penta = five
hexa = six
hepta = seven
octa = eight
ennea = nine
deca = ten
• P2O5
diphosphorous pentaoxide
• AsO2
arsenic dioxide
Remember your valence list is NOT all inclusive!
• SF6
sulfur hexafluoride
11
What do we find here that we
have not yet considered?
• K3PO4
•
• (NH4)2SO4
potassium phosphate
• Ca(OH)2
calcium hydroxide
• N2 (SO4)5
dinitrogen sulfate
ammonium sulfate
• What is the rule that is used here?
12
Polyatomic Ions
• Use previous rules
• Polyatomic Ions (Radicals) NEVER CHANGE THEIR
NAME in any way!
• Na2SO4
sodium sulfate
• N2(CO3)5
dinitrogen carbonate
• NH4Br
ammonium bromide
• Fe(NO3)2
iron II nitrate
13
If the first element is a…
Metal
1 + valence
•
•
•
•
•
Name 1st element
Name 2nd element
w/ -ide ending
Metal
2 + valences
Name 1st element
Charge in Roman
numeral
Name 2nd element
w/ -ide ending
NONmetals
Prefixes
Name 1st element
Name 2nd element
w/ -ide ending
Polyatomic ions never change / modify their names.
The first element in the compound determines how the compound will be named.
Only one method of naming is used to name a compound.
14
More than one positive valence…
…the old way
• Traditional Method
• Name the first element, but modify to include either
an -ous or -ic suffix.
•
•
•
The HIGHER valence uses the -IC ending.
The LOWER valence uses the -OUS ending.
Name the nonmetal, but modify to have an -ide
ending
CoN
cobaltic nitride
Co3N2
cobaltous nitride
15
More than one positive valence…
…the old way
• Some elements will revert to using their
Latin names for this purpose. Refer to
your sheet of ‘Common Cations.’
• Cu2S
cuprous sulfide
• SnS2
stannic sulfide
16
If the first element is a…
Metal
2 + valences
Metal
1 + valence
NONmetals
Stock
Traditional
(new)
(old)
•
•
Name 1st element
Name 2nd element
w/ -ide ending
Name 1st element Name 1st element
Charge in Roman Add –ous (lower)or
numeral
-ic (higher) valence
nd
Name 2 element Name 2nd element
w/ -ide ending
w/ -ide ending
•
•
•
Polyatomic ions never change / modify their names.
The first element in the compound determines how the compound will be named.
Only one method of naming is used to name a compound.
Prefixes
Name 1st element
Name 2nd element
w/ -ide ending
17