HOMEWORK PROBLEMS CHAPTER 2 (ii), CHAPTER 3
A metal is a substance that has characteristic luster, or shine, and is generally a good
conductor of heat and electricity. Most metals are solids at room temperature (mercury is
the sole exception).
010. The answer is c: magnesium hydroxide, Mg(OH)
Errors: a) Na
S is sodium sulfide (typical binary compound); sodium sulfite is Na
b) Calcium carbonate contains the Ca
ions, so has formula: CaCO
d) Ions must show the charge, so the nitrite ion is NO
is called nitrogen dioxide (it is a foul-smelling, poisonous, brown gas)
e) Iron(III) oxide contains the Fe
ions, so has formula Fe
FeO must contain the Fe
ion and would be called iron(II) oxide.
2.76 a. Co
Check that the total positive and negative charges in each compound are equal
2.78, 86, 122, 124. The three general types of compounds with which we are concerned
are molecular (no metals); ionic with a Group I, II metal or Al; and ionic with a transition
Molecular compounds: use a Greek prefix to indicate subscript value (pages 65-6
Ionic compounds, with Gp I, II and Al: give name of cation followed by name of
anion (page 62)
Ionic compound with transition metal (which can often have more than one
charge for its ions): include the cation charge as a Roman numeral (page 62)
2.78 a. Na
sodium oxide (Group IA forms only 1+
manganese(III) oxide (compound of transition metal).
copper(II) nitrate (compound of transition metal).
: more complete answers for (a), (b):
To do this, you must first observe that the compound is ionic since it
involves a metal and a non-metal.
Then, you must observe sodium, Na,
is a group IA metal.
Therefore, it will have a +1 charge as an ion.
Thus no Roman numeral is needed.
Next you must find the name for the anion and cation.
Since the rule
is that monatomic cations are named after the element if there is only
one such ion, which is true in sodium’s case, Na+ is called the sodium
The concept for the names of the monatomic anions is that the
name is obtained from a stem name of the element followed by the suffix
Oxygen has the stem name ox- so the name of the oxygen anion
would be oxide.
The last concept in naming is that the name of the
cation is followed by the name of the anion.
Therefore, using logic, I
now know the name for the compound.
It would be sodium oxide.