Question
______ form ions with a 2+ charge when
they react with nonmetals.
a)
b)
c)
d)
e)
Group IA elements
Group IIA elements
Group VIIA elements
Group VIIIA elements
None of the above
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Answer
b) Group IIA elements
Group IIA elements form ions with 2+
charge and combine with nonmetals in
binary compounds.
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Question
Which is not the correct chemical formula
for the compound named?
a)
b)
c)
d)
e)
Potassium phosphate, K3PO4
Iron(II) oxide, FeO
Calcium carbonate, CaCO3
Sodium sulfide, NaS
Lithium nitrate, LiNO3
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Answer
d)
Sodium sulfide, NaS
Sodium sulfide is a binary compound composed
of a Group IA element whose charge in
compounds is +1 and a Group VIA element
whose charge in binary compounds is
commonly –2. This means that two sodium ions
must be combined with one sulfide ion for a
neutral compound.
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Question
Which of the following is not the correct
chemical formula for the compound
named?
a)
b)
c)
d)
e)
Li2O, lithium oxide
FePO4, iron(III) phosphate
HF, hydrogen fluoride
BaCl2, barium dichloride
Mg3N2, magnesium nitride
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Answer
d)
BaCl2, barium dichloride
The binary compound, BaCl2, is
composed of a metal and a nonmetal.
Since barium forms only one ion, the
name is barium chloride (no prefix is
needed).
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Question
Which is the correct formula for copper(I)
sulfide?
a)
b)
c)
d)
e)
CuS
Cu2S
CuS2
Cu2S2
None of the above
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Answer
b)
Cu2S
The copper(I) ion has a +1 charge and the
sulfide ion has a −2 charge.
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Question
Which of the following is the correct
chemical formula for iron(III) oxide?
a)
b)
c)
d)
e)
FeO
Fe3O
FeO3
Fe3O2
Fe2O3
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Answer
e)
Fe2O3
The iron(III) ion has a +3 charge and the
oxide ion has a −2 charge.
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Question
What is the correct name for this
compound with the formula Mg3(PO4)2?
a)
b)
c)
d)
e)
Trimagnesium diphosphate
Magnesium(II) phosphate
Magnesium phosphate
Magnesium(II) diphosphate
Magnesium(III) diphosphate
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Answer
c)
Magnesium phosphate
The magnesium ion has only one possible
charge (a +2 charge) and the phosphate
ion has a −3 charge.
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Question
What is the correct name for this
compound with the formula CS2?
a)
b)
c)
d)
e)
Monocarbon disulfide
Carbon disulfur
Carbon disulfide
Carbon sulfide
Carbon(VI) sulfide
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Answer
c)
Carbon disulfide
There is one carbon, but the mono- prefix
is not used for the first element. There
are two sulfur atoms, so a di- prefix is
used. The name ends with an -ide ending.
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Question
What is the correct formula for
hypobromous acid?
a)
b)
c)
d)
e)
HBr
HBrO
HBrO2
HBrO3
HBrO4
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Answer
b) HBrO
HBrO3 is bromic acid.
Removing one O gives HBrO2 or bromous
acid.
Removing one more O gives HBrO or
hypobromous acid.
Removing the last O gives HBr or hydrobromic
acid.
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Question
What is the correct formula for the
compound barium hydroxide octahydrate?
a)
b)
c)
d)
e)
BaOH
Ba(OH)2
Ba(OH)2 . 8H2O
Ba(OH)2(H2O)8
BaOH . 8H2O
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Answer
c) Ba(OH)2 . 8H2O
The barium ion has a charge of +2, so there are
two hydroxide groups in the formula. Waters of
hydration are written at the end of the formula
separated by a dot, with the number of waters
of hydration defined using Greek prefixes.
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