Download Nomenclature Part II: Hydrates and Molecular

SCH3U – Matter and Bonding
Nomenclature Part II: Hydrates and Molecular compounds
Properties of Ionic Compounds
 Cations and anions form a regular repeating pattern producing a ________________________
in which the ions are in _________________.

Attraction between oppositely charged particles is _________

Melting and boiling point – because the forces holding the molecules together are quite strong
they have ____________ melting and boiling points

Solubility in water – __________ are soluble in water, but some are _______ (solubility rules).

Conductivity – ionic compounds form ________. Therefore they ______conduct electricity when
dissolved in water.
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Hydrates
Hydrates are ionic compounds that have __________ as part of their chemical structure. The name of
the compound is given, followed by the suitable ____________ for the number of water molecules
present, and finally ending in “_____________”.
e.g. MgCl26H20 – Magnesium chloride ______________________. Notice the placement of
the . This formula indicates that there are six water molecules weakly bonded to each MgCl2 formula
unit.
Ionic compounds often absorb water, and are described as being hygroscopic. From Greek
“hygro-“ which means wet. When the compound is dehydrated, we describe it as being in its
_________________ form.
Molecular Compounds
Covalent or Molecular compounds form when two ________________ combine.
Molecular compounds have properties that distinguish them from ionic compounds.

Solubility in water – __________ are soluble in water, but most are _______.

Melting and boiling point – the forces holding the molecules together are quite ________– they
have ________ melting and boiling points

Conductivity – molecular compounds do not form ________. Therefore they ____________
conduct electricity when dissolved in water.
Systemic Names (Prefix System)
Prefix
mono
di
tri
tetra
penta
hexa
hepta
octa
nona
Deca
Number
Writing
Formulas:
1. Write the symbol of each element in the same order as in the name.
2. The prefix of each element indicates the number of atoms in the
formula, so the formula needs a subscript that matches the prefix (no
prefix means a subscript of 1). Do not cross-over any numbers.
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Examples:
dinitrogen pentoxide
carbon dioxide
___________________________
____________________________
Writing Names:
1. Given the formula, write the name of each element in the same order.
2. Use the subscripts to determine the prefix for each element in the
name. If there is no subscript, use the prefix “mono” (“mono” can be left
off of the first element).
Examples:
PCl5
NF3
___________________________
____________________________
Exercises
1. Write the correct formulas for the following:
1. nitrogen pentachloride
6. silicon tetrachloride
2. silicon tetrabromide
7. carbon monoxide
3. arsenic trioxide
8. diarsenic trisulfide
4. carbon disulfide
9. phosphorus hexafluoride
5. carbon tetrachloride
10. dihydrogen monoxide
2. Write names for the following, using prefix rules
1. AsI3
6. SiBr4
2. CCl4
7. N2S3
3. NH3
8. SiO2
4. CS
9. PF3
5. P2S5
10. CCl4
3. How is a hydrate different from other chemical compounds?
4. Define the following terms:

anhydrous

dehydration
5. Name the following compounds:
a)
FeCl3. 6 H2O ___________________________________________
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b)
CuSO4 . 5 H2O _________________________________________
c)
CuCl2. 5 H2O _________________________________________
6. Write the formulas for the following compounds:
a)
barium chloride dihydrate _________________________________
b)
magnesium sulfate heptahydrate ___________________________
7. Give names and/or formulae for the following
1)
NaF
13) potassium fluoride
2)
K2CO3
14) ammonium sulfate
3)
MgHCO3
15) magnesium iodide
4)
Be(OH)2
16) copper (II) sulfite
5)
SrClO4
17) aluminum phosphate
6)
CuCH3COO
18) lead (II) nitrite
7)
ZnCrO4
19) cobalt (II) permanganate
8)
Ca3(PO4)2
20) silver cyanide
9)
NH4NO2
21) copper (II) bicarbonate
10)
Mn(NO3)3
22) iron (II) peroxide
11)
Fe3(PO4)2
23) lithium cyanide
12)
CoCO3
24) lead (IV) sulfite
8. Describe how a blind person might determine whether a compound is ionic or covalent if they were
working alone in a laboratory.
9. Write the names of everyday objects that have the same shapes as the following molecular shapes.
linear: ______________________________________________________
bent: _______________________________________________________
trigonal pyramidal: ____________________________________________
trigonal planar: _______________________________________________
tetrahedral: __________________________________________________
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