Chapter 8 Review Flashcards
1
Q
Bonds tend to form to give . . . electron configurations
A
more stable
2
Q
Bond form to give more stable electron configurations by . . .
A
losing, sharing, and gaining electrons
3
Q
The three types of bonds are . . .
A
Ionic bonds, Covalent bonds, and Metallic bonds
4
Q
Ionic bonds have a . . . of electrons
A
complete transfer
5
Q
Because ionic bonds have a complete transfer of electrons, the ions in that bond have . . .
A
opposite charges
6
Q
The electrons in covalent bonds are ______
A
shared
7
Q
Metallic bonding results in . . .
A
delocalized valence electrons which are
electrostatically attracted to fixed metal nuclei.
8
Q
Ionic bonding has . . .
A
electrostatic attractions (typically between a metal and a nonmetal)
9
Q
Covalent bonding has . . .
A
Shared electron pairs (typically between two nonmetals)
10
Q
Metallic bonding can be referred to as a . . .
A
“sea of electrons”
11
Q
The electrons involved in chemical bonding are called . . .
A
valence electrons
12
Q
An element’s Lewis symbol consists of . . .
A
the element’s chemical symbol and a dot for each valence electron
13
Q
Most ions have a . . . electron configuration
A
noble gas
14
Q
A noble gas configuration is . . .
A
ns^2 np^6
15
Q
Noble gases have a very ______ electron configuration
A
stable
16
Q
The octet rule says that . . .
A
Atoms tend to lose, gain or share electrons until they are surrounded by 8 valence electrons (full s and p subshells in an atom)
17
Q
Ions that DO NOT have noble gas configurations are . . .
A
H, He, and most transition metals
18
Q
Because H, He, and most transition metals do not have noble gas configurations, they don’t . . .
A
follow the octet rule
19
Q
Ionic bonding results from the electron transfer between . . .
A
positive cations and negative anions
20
Q
Low ionization energy (metals) =
A
cations
21
Q
High electron affinity (nonmetals)=
A
anions
22
Q
Some characteristics of Ionic compounds include:
A
- Hight melting points
- High heats of fusion and vaporization
- Electrical insulators when solid
- Electrical conductors when molten or
dissolved in water - Hard and Brittle
23
Q
The formation of ionic compounds is
very . . .
A
exothermic
24
Q
Ionic compounds are . . .
A
very stable
25
The pattern that cations and anions organize themselves in is called a . . .
lattice
26
A crystal lattice is . . .
an arrangement of ions of opposite charge
surrounding one another in three dimensions
27
The strong attraction of the cations to anions in a lattice can be measured as . . .
lattice energy
28
Lattice energy is . . .
the energy (kJ/mol) needed to completely separate 1 mole of a solid ionic compound into its cations and anions
29
What would an equation for lattice energy of cation X and anion Y look like?
XY(s) --> X(+)(g) + Y(-)(g)
30
An equation to find lattice energy is . . .
Eel = (k*Q1*Q2)/d
31
Lattice energy, crystal stability, and ionic bond strength increase as . . .
Ionic charges (Q1 and Q2) increase or atomic radii (d) decrease
32
When it comes to lattice energy, between ionic charge and atomic radii, which of those two factors has a greater effect on lattice energy?
Ionic charge
33
What physical properties does the lattice energy affect?
1. Melting Point
2. Boiling Point
3. heats of fusion (ΔHfus) and vaporization (ΔHvap)
34
Covalent bonding generally occurs between
nonmetals
35
Covalent bonds share electrons to try to get a . . . configuration
Noble Gas
36
Covalent bonds can be represented with . . .
Lewis Symbols
37
Covalent bonds form by . . .
sharing one or more pairs of electrons
38
Some characteristics of Covalent molecules are . . .
1. Low melting points and boiling points
2. Low heats of fusion and vaporization
3. Poor conductors of heat and electricity
4. More likely to be flammable
5. Soft, brittle solids
39
When a molecular substance melts or boils, the covalent bonds . . .
do not break
40
when a molecular substance melts or boils, what happens is that . . .
intermolecular interactions are broken
41
In Lewis structures, shared electrons are drawn as . . .
bonds
42
In Lewis structures, nonbonding electrons are drawn as . . .
dots
43
In Lewis structures, the electrons that are able to be shared are . . .
the dots
44
What happens when atoms form bonds but there’s a “scarcity” of valence electrons?
they form double or triple bonds
45
To achieve an octet with the available valence electrons, atoms . . .
can share more than one pair of electrons.
46
A single bond is when
two atoms share one electron pair
47
A double bond is when
two atoms share two electron pairs
48
A triple bond is when
two atoms share three electron pairs
49
A single bond has a bond order of
1
50
A double bond has a bond order of
2
51
A triple bond has a bond order of
3
52
When two atoms collide, but do not bond, the closest distance between the two nuclei is called . . .
the apparent radii
53
The apparent radii are . . .
the nonbonding atomic radii
54
When atoms are in a chemical bond, the nuclei are closer together, this radius is referred to as . . .
the bonding atomic radii
55
When talking about molecular radii, we use . . .
bonding atomic radii
56
Provided we know the bonding atomic radii of two elements, we can calculate . . . between those two atoms within a molecule.
the bond length
57
Bond strengths and bond lengths contribute to . . .
reactivity and thermodynamics
58
Bond Enthalpy is also symbolized by . . .
D
59
Bond Enthalpy is . . .
the enthalpy change (ΔH) for the breaking of a particular bond in one mole of a gaseous substance
60
Since breaking bonds REQUIRES energy, bond enthalpies are always . . .
positive qualities
61
The greater the bond enthalpy, . . .
the stronger the bond
62
The stronger the bond, . . .
the greater the bond enthalpy
63
Most reactions proceed with bond breakage and formation are . . .
simultaneous
64
Bond polarity is . . .
a measure of how equally, or unequally, the electrons in a covalent bond are shared
65
Bond polarities can be . . .
nonpolar covalent, polar covalent, or ionic
66
What leads to an unequal sharing of electrons between two atoms?
Differences in electronegativity between the two atoms
67
In a compound, the atom that pulls the electrons to itself the most is . . .
the most electronegative atom
68
asymmetric charge distribution results in . . .
polar bond
69
When two atoms share electrons unequally, a . . . results
bond dipole
70
A dipole moment is measured in . . .
Debyes
71
1 Debyes is equal to . . .
3.34 x 10^-34 C*m
72
To compare and determine bond polarity, . . .
you can use the difference in electronegativity values (ΔEN)
73
When the difference in electronegativity values is smaller than 0.5, the bond is . . .
usually nonpolar covalent
74
When the difference in electronegativity values is between o.5 and 1.6, the bond is . . .
usually polar covalent
75
When the difference in electronegativity values is between 1.6 and 2.0, the bond is . . .
polar covalent if the two atoms are nonmetals and ionic if one of the two atoms is a metal
76
When the difference in electronegativity values is greater than 2, the bond is . . .
usually ionic
77
The greater the difference in electronegativity, the larger . . .
the dipole moment
78
The larger the dipole moment, the
more . . .
polar is the bond
79
The first step in drawing a Lewis structure
count the number of valence electrons
80
When counting the number of elections and accounting for a cation, . . .
subtract one electron from the total for each positive charge
81
When counting the number of electrons and accounting for an anion, . . .
add one electron from the total for each negative charge
82
The second step in drawing a Lewis structure
Look at the chemical formula and decide which atom is the CENTRAL atom
83
The central atom is usually . . .
written first and is the least electronegative element
84
Chemical formulas are often written in the order . . .
the atoms are connected
85
The third step in drawing a Lewis structure
draw a molecular “skeleton” connecting all outer atoms to the central atom with single lines
86
The fourth step in drawing a Lewis structure
complete the octets for the all of the outer atoms using lone pairs
87
Because hydrogen can only make one bond, hydrogen will only have . . .
2 electrons
88
The fifth step in drawing a Lewis structure
place any excess electrons (as lone pairs) on the central atom
89
A central atom can have more than eight electrons if it is . . .
in Row 3 of the Periodic Table or below
90
If there are not enough electrons to give the central atom an octet, then . . .
shift lone pair electrons from outer atoms to form multiple bonds and satisfy the octet rule
91
The most dominant Lewis structure has . . .
an overall formal charge equal to 0 and when the most electronegative atom has the negative charge
92
Formal charge is equal to . . .
Number of valence electrons - lines - dots
93
When multiple correct Lewis structures can be drawn, . . .
the structures are called resonance structures
94
The different resonance forms represent . . .
delocalized bonding
95
Resonance indicates . . .
increased stability in the structure
96
The first exception to the octet rule is . . .
Ions or molecules with an odd number of electrons
97
The second exception to the octet rule is . . .
Ions or molecules with less than an octet
98
The third exception to the octet rule is . . .
Ions or molecules with more than eight valence electrons (an expanded octet)
99
If there is an odd number of valence electrons, one atom, usually the central atom will contain . . .
7 instead of 8 electrons
100
The 4 atoms that can have less than 8 electrons are . . .
B, Be, H, and Al
101
B needs _ electrons
6
102
Be needs _ electrons
4
103
H needs _ electrons
2
104
Al needs _ electrons
6
105
Atoms that can have more than an octet are . . .
Period 3 or below
106
When atoms have more than 8 electrons, they are called . . .
hypervalent
107
Hypervalent atoms are usually surrounded by . . .
small, highly electronegative atoms
