l0Z:
Chapter
3
Chemical Bonds
3.44 Write
3.45
the formula for the ionic compound formed
from the following pairs of ions:
(a) Iron(II) ion and chloride ion
(b) Calcium ion and hydroxide ion
(c) Ammonium ion and phosphate ion
(d) fin(Il) ion and fluoride ion
Which formulas are not correct? For each that is not
cor:rect, write the correct formula.
(a) Ammonium phosphate; (NH)2POa
(b) Barium carbonate; Ba2CO3
(c) Aluminum sulfide; A12S3
(d) Magnesium sulfrde; MgS
--3.d;2 Name these ionictompounds:
(a) NaF
ft) MgS
3.54 Write formulas for the following ionic
compound.
(c) The formula of aluminum oxide is Al2O3.
(d) Both copper(Il) oxide and cupric oxide are
acceptable names for CuO.
(e) The systematic name for Fe2O3 is iron(Il) oxide.
3.4!t
=
3.49
Potassium chloride and potassium bicarbonate are
used as potassium dietary supplements. Write the
formula of each compound.
Potassium nitrite has been used as a vasodilator and
as an antidote for cyanide poisoning. Write the for-
mula of this compound.
3.50
Name the polyatomic ion(s) in each compound.
(a) Na2SO, (b)
KNO3
(c) CszCOs
(d) NH4OH (e) I(zHPOa
3.51 Write
the formulas for the ions present in each
compound.
(a) NaBr
(d)
KH2PO4
(b)
(e)
FeSO, (c) Mgs(POJz
NaHCO, (fl Ba(NOr),
compounds:
compounds:
(c) Strontium dihydrogen phosphate
(d) Silver carbonate
(e) Strontium chloride
(f) Barium permanganate
Section 3.7 What ls a Covalent Bond?
3.55
Answer true or false.
(a) A covalent bond
is formed behareen hnro atoms whose
difference in electronegativity is less than 1.9.
(b) If the difference in electronegativity between two
atoms is zero (they have identical electronegativities), then the two atoms will not form a covalent bond.
(c) A covalent bond formeil by sharing two electrons
is called a double bond.
(d) In the hydrogen molecule
(Hz), the shared pair
of electrons completes the valence shell of each
hydrogen.
(e) In the molecule CHa,
(f) The systematic name for FeCO3 is iron carbonate.
(g) The systematic name for NaH2POa is sodium dihydrogen phosphate.
(h) The systematic name for I$HPO4 is dipotassium
hydrogen phosphate.
(i) The systematic name for Na2O is sodium oxide.
(j) fne systematic name for PCl3 is potassium
chloride.
(k) The formula of ammonium carbonate is NHaCO3.
G)(NHr,HPO4
(a) Ammonium hydrogen sulfite
(b) Magnesium acetate
(c) Sodium hydrogen phosphate; NaHPOa
Answer true or false.
(a) The name of a binary ionic compound consists of
the name of the positive ion followed by the name
of the negative ion.
(b) In naming binary ionic compounds, it is necessary
to state the number of each ion present in the
BaHz
(a) Potassium bromide (b) Calcium oxide
(s) Mercury(Il) oxide
(d) Copper(Il) phosphate
(e) Lithium sulfate
(0 Iron(III) sulfrde
(b) Lithium oxide;LiO
3.47
Fe(OH)z (i) NaHzPOa
3.53 Write formulas for the following ionic
correct? For each that is not
correct, write the correct formula.
(a) Calcium oxide; CaO2
Section 3.6 How Do We Name lonic
Compounds?
(h)
0) Pb(CHaCOO), (k)
3.46 Which formulas are not
(d) Ammonium nitrate; NH4NOS
(c) Al2O3
(e) Ca(HSOs)z (f) KI
(d) BaCl,
(g) Srs(Porz
(f)
each hydrogen has an elec-
tron configuration like that ofhelium and carbon
has an electron configuration like that ofneon.
In a polar covalent bond, the more electronegative atom has a partial negative charge (6-) and
(g)
the less electronegative atom has a partial positive charge (6+).
These bonds are arranged in order ofincreasing
(h)
These bonds are arranged in order ofincreasing
polarity
polarity
(i)
C-H
H-F
<
<
N-H
H-Cl
<
<
O-H.
H-Br.
A polar bond has a dipole with the negative end
located at the more electronegative atom.
0) In a single bond, two atoms share one pair of
electrons; in a double bond, they share two pairs
ofelectrons; and in a triple bond, they share
three pairs of electrons.
(k) The Lewis structure for ethane, C2H6, must shod!
eight valence electrons.
0) The Lewis structure for formaldehyde, CH2O,
must show 12 valence electrons.
(m) The Lewis structure for the ammonium ion,
NHa+, must show nine valence electrons.
(n) Atoms of third-period elements can hold more
than eight electrons in their valence shells.