Chapter 7& 8 Book problems: BONDING: Ionic, covalent, metallic
Chapter 7: 2, 10, 12, 13, 15, 19, 20, 24, 25, 31, 32, 44, 49, 67,
Chapter 8: 1, 2, 5, 12, 13, 15, 22, 28, 29, 30, 31, 36, 37, 41, 42, 43, 45, 49, 50, 58, 59, *74
ANSWERS:
Chapter 7:
2)
a) 2 electrons lost
b) 3 e- gained
c) 2 e- lost
10)
a) potassium cation, K+
b) Zinc cation, Zn2+
c) fluoride anion, F1-
12)
a) KI
b) Al2O3
13) CaCl2
15)
Usually a solid at room temperature; high melting point; conduct electricity when melted or dissolved
19)
a) BaCl2 b) MgO
20)
B and d are ionic; Li, Cl and I, Na
24)
Compact and orderly manner of atoms in metal.
c) Li2O
d) CaF2
Or Positive particles (nuclei and inner shell electrons) surrounded by a “sea of electrons”
25)
The properties of alloys are often superior (for a particular task) to teir original elements
31)
a) gain 1 electron
Br-
bromide anion
b) lose 1 electron
Na+
sodium cation
c) gain 3e-
As3-
arsenide anion
d) lose 2 e-
Ca2+
calcium cation
e) lose 1 e-
Cu1+
copper(I) cation
f) gain 1 e-
H-
hydride ion
32)
see above
44)
a) S and O will not form ionic
b) Na and Ca will not form ionic
c) Na and S WILL form an ionic compound
d) O and Cl will not form ionic
49)
See page 202
Body centered cubic: Na, KJ, Fe, Cr or W
Face centered cubic: Cu, Ag, Au, Al, or Pb
Hexagonal close packed: Mg, Zn or Cd
67)
a,c,e and F are not ionic ( H2O, CO2, SO2 and NH3; these are molecular)
B and d are most likely ionic (Na2O and CaS)
Ch 8:
1) Yes, molecules have lower melting and boiling points
2) How many atoms of each element one molecule of a compound contain
5) N2 (about 80%) and O2 (about 20%)
12)
13) Those of a noble gas (complete s and p orbital (usually a full octet)
15) When by sharing 2 or 3 PAIRS of electrons they gain a stable octet
22) The H-H bond is stronger than the C-C bond (it takes more energy to break it)
28) C2H2 has two single bonds and a triple bond (which is really a sigma and 2 pi bonds) for a total of Three(3) sigma and
Two(2) pi (see picture on page 236)
29) this shape (one in the center surrounded by 4) is called TETRAHEDRAL
30)
a) H and Br; Moderately polar covalent
b) K and Cl; ionic
c) C and O; moderately to very polar covalent
d) Cl and F; moderately to very polar covalent
e) Li and O; ionic
f) Br and Br; 100% nonpolar covalent
31)
least to most polar: H-S and H-C (tie); H-Br; H-Cl
36)
The atoms in CCl4 are oriented so that the bond polarities cancel; some molecules with polar bonds are nonpolar molecules due to symmetry
37) (see images above)
41) nitrogen (N2) is a diatomic MOLECULE and so is Oxygen (O2) argon would be an atom
42) Neon is a filled outer shell (8 electrons) Chlorine needs to “share” with another chlorine atom to seem to have a
filled outer shell
43)
MgCl2 is IONIC; Na2S is IONIC; H2O is covalent; H2S is covalent
45)
A double covalent bond has 4 (2 pairs) of shared electrons; A triple bond has 6shared electrons (3 pairs)
49)
50) PCl2F3 and SF4 do not follow the octet rule: they end up with a center atom that has 10 electrons around it
58) Most polar first to least polar: c,d,a,f,b,e
H-F; H-O; H-Cl; S-Cl; H-C; H-H
59) A hydrogen bond is formed by an electrostatic interaction between a hydrogen atom that is covalently bonded to an
electronegative atom, and an unshared electron pair of a nearby atom.
74) The shape of the molecule is different: The ethyl alcohol can form intermolecular hydrogen bonds between its polar
–OH groups, but dimethyl ether cannot form hydrogen bonds