Bonding Flashcards
1
Q
Define electron affinity.
A
The energy change when a neutral atom attracts an electron to become a negative ion.
- Electron affinity indicates how likely an atom is to gain an electron.
2
Q
Fill in the blank: A metallic bond is the _______ between the positive metal ions and the negative sea of electrons.
A
electrostatic force of attraction
This describes the nature of metallic bonding.
3
Q
List three properties of metallic substances attributed to its bonding structure.
A
- Good conductors of heat
- Good conductors of electricity
- Malleable and ductile
4
Q
What is stereochemistry?
A
The study of three-dimensional shapes that molecules form.
5
Q
What is the key force of ionic compounds?
A
The electrostatic attraction between cations and anions.
6
Q
A
7
Q
What states do non-metals form when combined?
A
Solids, liquids, or gases
- Non-metals can exist in various states depending on their molecular structure and temperature.
8
Q
What defines covalent bonds?
A
Bonds formed between non-metallic atoms by sharing electrons to obtain a full valence.
9
Q
Which metals are considered precious metals?
A
Gold, silver, and platinum
Precious metals are valued for their rarity and economic significance.
10
Q
What are the exceptions to the octet rule? Name one.
A
Hydrogen needs only two valence electrons to be stable.
11
Q
What is the main goal of bonding in molecular compounds?
A
Bonding involves sharing electrons to obtain a full valence.
12
Q
What is the bond pair and lone pair count for a tetrahedral molecule?
A
Bond pairs = 4, lone pairs = 0.
13
Q
How can the formation of sodium fluoride be represented?
A
Using electron dot diagrams.
14
Q
What should be completed to fulfill the octet rule?
A
Add as many atoms of the other element as are needed to complete the octet of the central atom.
15
Q
What are the two questions to ask when determining if a molecule is polar or nonpolar?
A
- Is there a lone pair on the central atom? 2. Are the surrounding atoms the same or different?
16
Q
Which element has a weaker attraction for electrons, sulfur or boron?
A
Boron, due to its smaller electronegativity.
Understanding these comparisons is vital for predicting chemical behavior.
17
Q
In a Lewis structure, how are bond pairs and lone pairs represented?
A
Bond pairs are represented with lines, and lone pairs are included in the diagram.
18
Q
Why do non-metals have relatively high electronegativity values?
A
Because non-metals gain electrons to obtain an octet (full shell).
This characteristic enhances their reactivity.
19
Q
What properties of water are attributed to its polarity?
A
High surface tension and high melting point.
20
Q
What is a fundamental skill necessary for understanding molecular compounds?
A
Applying knowledge of electron dot diagrams and the octet rule.
21
Q
How do molecular formulas differ from ionic formulas?
A
Unlike ionic formulas, molecular formulas are NOT reduced to show the simplest ratio.
22
Q
What are intramolecular bonds responsible for?
A
Chemical properties of a substance
23
Q
What are intermolecular forces responsible for?
A
Physical properties of a substance
24
Q
Fill in the blank: A nonpolar molecule has a _______ electron distribution.
A
symmetrical
25
What is a nonpolar covalent bond?
A covalent bond in which electrons are shared equally between the two atoms involved.
26
Which element is more reactive, barium or potassium?
Potassium, because it has to lose only 1 electron.
## Footnote
This example shows how the number of valence electrons affects reactivity.
27
What is the bond pair and lone pair count for trigonal planar molecule?
Bond pairs: 3
Lone pairs :0
28
What are valence electrons?
Electrons in the outermost energy level of an atom involved in chemical bonding
- Valence electrons determine an atom's chemical properties.
29
What is the bonding capacity used for?
To identify the number of bonds an atom will form.
30
Based on electronegativity values, which element has a stronger attraction for electrons, carbon or chlorine?
Chlorine, because it has a higher electronegativity.
## Footnote
This comparison illustrates the concept of electronegativity in practice.
31
What is a bonding continuum?
A gradual transition from one set of conditions to another set of conditions.
32
What is the result of unequal sharing of electrons in a polar covalent bond?
A partial charge on each of the atoms involved.
33
resonance structure:
- more than one possible lewis structure
- two identical bonds have properties that could be described as halfway between a single bond and a double bond
- structures are changing back and forth between each other
34
What is a structural formula?
A model that only shows atoms and bonds, eliminating lone pairs of electrons.
35
How can electron dot diagrams represent diatomic elements?
Electron dot diagrams can show how two fluorine atoms share a pair of electrons to form a covalent bond.
36
What do ionic compounds need to maintain?
A neutral charge.
37
How do you determine the number of valence electrons for an element?
Use the group number of the element.
38
What is the first step in drawing electron dot diagrams for molecular compounds?
Determine the total number of valence electrons in all the atoms in the molecule.
39
What are dipole-dipole forces?
Forces that occur in polar molecules due to attraction between partially positive and negative ends
40
what difference in electronegativity(DEN) suggests non polar covalent vs polar covalent, vs ionic bonds?
NON POLAR COVALENT= 0
POLAR COVALENT= Between 0.1 and 1.7
IONIC= Above 1.7
41
What represents a single bond in electron dot diagrams?
A pair of electrons drawn between each pair of atoms.
42
mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms
together is called a(n)?
chemical bond
43
What are London Dispersion Forces?
A type of intermolecular bonding
44
What characterizes the structure of metallic bonds?
A network of positive metal ions in a sea of electrons
## Footnote
This allows for the delocalization of valence electrons.
45
What does it mean that nonpolar substances mix with each other?
They can interact due to similar charge distributions.
46
What is the relationship between electronegativity and reactivity in metals?
The lower the electronegativity value, the less attraction for electrons, making it easier for that atom to lose valence electrons and thus more reactive.
## Footnote
This is a general trend observed in metallic elements.
47
If the surrounding atoms of the central atom are the same, what type of molecule is it?
Nonpolar.
48
Fill in the blank: The greater the number of electrons, the stronger the _______ forces.
London dispersion
49
Which molecules exhibit stronger dipole-dipole forces?
More polar molecules
50
What is the key to communicating ionic formulas?
Reducing the ratio of cations and anions to the lowest ratio.
51
How can the type of bond formed be identified?
Based on differences in electronegativity and classification of elements involved.
52
What does MORE intermolecular forces mean in terms of melting/boiling points?
**MORE** IMF = **HIGH** melting/boiling points
53
Which metal has the lowest electronegativity value?
Francium (0.7).
- Francium's low electronegativity makes it the most reactive metal.
54
coordinate covalent bond:
one of the atoms can contribute to both the electrons instead of just one of the two
55
Order the electron-pair repulsion from greatest to least.
Lone pair-lone pair > lone pair-bonding pair > bonding pair-bonding pair.
56
What is metallic bonding?
The electrostatic force of attraction between the positive metal ions and the negative sea of electrons
## Footnote
Metallic bonding involves delocalized valence electrons that are shared among all atoms.
57
What does the delta positive (𝜹+) symbol indicate?
The atom with the lower electronegativity value has the bonding pair of electrons pulled away from it.
58
What is the significance of electronegativity in bonding?
It helps determine the type of bond that forms based on the difference in electronegativity values.
59
How are the number of valence electrons determined for groups 1 and 2?
They have 1 and 2 electrons respectively
- For groups 13-18, the group number minus 10 indicates the number of valence electrons.
60
What properties do intermolecular forces affect?
Boiling point, melting point, surface tension, solubility, vaporization, viscosity, and volatility
**Physical
61
In VSEPR theory, what does 'E' represent?
A lone pair.
62
How does the nucleus of a non-metallic atom affect electron transfer?
It has a stronger electrostatic attraction for electrons, pulling them to form a negative ion.
63
What are the five stereochemical shapes required to know in chemistry 20?
* Linear (180°C)
* V-shaped (bent or angular)
* Trigonal planar (120°C)
* Trigonal pyramidal
* Tetrahedral (109.5°C)
64
What is ore?
Natural rock or sediment containing valuable minerals, typically metals
## Footnote
Ore is mined for the extraction of metals and other valuable materials.
65
What are bonding electrons from different elements called?
Bonding pairs.
66
How are bonds represented in structural formulas?
A line represents each bond pair of electrons.
67
What are intramolecular bonds?
Bonds formed within a molecule that are relatively strong.
68
Fill in the blank: The atom with lower electronegativity in a polar covalent bond is ______.
partially positive (𝜹+)
69
What is ionization energy?
The energy required to remove an electron from a neutral atom.
## Footnote
Ionization energy is a key concept in understanding how atoms interact with electrons.
70
In which molecules is the only intermolecular force present London dispersion force?
Nonpolar molecules and noble gases
71
What does the period number indicate?
The number of energy levels occupied by electrons
## Footnote
The periodic table is organized in periods that reflect electron shell filling.
72
What does a higher electronegativity value indicate?
Greater attraction for another atom's valence electron
## Footnote
Electronegativity values help predict how atoms will interact in compounds.
73
True or False: Electronegativity values are meaningful on their own.
False
74
What type of bonding occurs in molecular compounds?
Full octets are formed by sharing electrons (covalent).
75
What type of elements compose molecular compounds?
Molecular compounds are composed from non-metallic elements.
76
What should be done if all valence electrons have not been accounted for?
Add one or more lone pairs around the central atom to complete an octet of electrons.
77
What questions should be asked after completing a bonding structure?
* Are all the open sites (bonding capacity) filled?
* Is the octet rule fulfilled?
* Valence electrons add up and are accounted for (e- pairs).
78
Why is the number of valence electrons for transition metals not predictable?
It depends on the environment around the ion
## Footnote
Transition metals can exhibit varying valence states.
79
What is hydrogen bonding?
An extremely strong dipole-dipole force, unique to certain molecules
80
What does the octet rule imply?
The outer shell of any compound or molecule is full
- This rule is a guideline, not an absolute rule in all cases.
81
What is the bond pair and lone pair count for a V-shaped (bent) molecule?
Bond pairs = 2, lone pairs = 2.
82
What is the central atom in an electron dot diagram?
The element with the largest bonding capacity.
83
What is the charge distribution in a water molecule?
Slightly negative on the oxygen side and slightly positive on the hydrogen sides.
84
What is a bond dipole?
A vector that shows the attraction of the electrons toward the more electronegative atom in a covalent bond.
85
What characterizes nonpolar molecules?
Equal charge distribution, resultant vector equals zero, and symmetrical charge distribution.
86
What is the rule for hydrogen in terms of electron configuration?
Hydrogen can only have two electrons in its outer shell.
87
What does it mean that polar substances mix with each other?
They can interact due to similar charge distributions.
88
What elements must be present for hydrogen bonding to occur?
Hydrogen bonded to fluorine, oxygen, or nitrogen
89
What are intermolecular forces?
The forces BETWEEN molecules
90
Fill in the blank: Ionic compounds exist in _______ structures.
crystal lattice
91
In VSEPR theory, what does 'X' represent?
Any atom bonded to the central atom.
92
What is the significance of a central atom's bonding capacity?
It determines how many other atoms can bond with it.
93
Which elements have the highest electronegativity values?
Fluorine, oxygen, nitrogen
94
What is the bonding capacity of an atom?
The maximum number of single covalent bonds that it can form.
95
Which element is more reactive, bromine or oxygen?
Oxygen, because it has a bigger electronegativity.
*** For non metals, lower EN means LESS reactivity unlike metals***
## Footnote
This highlights the trend of reactivity in non-metals.
96
What is the exception to metals being solids in their pure form?
Mercury (quicksilver)
- liquid at room temperature.
97
What largely influences the transfer of electrons in ionic bonds?
The difference in electronegativity between the metal and non-metal.
98
Define electronegativity.
Relative measure of an atom's ability to attract electrons in a chemical bond
## Footnote
Electronegativity values are listed on the periodic table.
99
Why do metals have relatively low electronegativity values?
Because metals lose electrons to obtain an octet.
## Footnote
This property contributes to their reactivity.
100
What is a Lewis structure?
A combination of electron dot diagrams and structural formulas.
101
What should be done if the central atom does not have an octet of electrons after using all valence electrons?
Move one or more lone pairs to form double or triple bonds.
102
What is the energy needed for decomposition of water?
285 kJ/mol
103
What are polar and nonpolar molecules?
Polar molecules have an asymmetrical charge distribution, while nonpolar molecules have a symmetrical charge distribution.
104
What does an electron dot diagram consist of?
The symbol for the element with its valence electrons around it.
105
What is the main focus of the study of bonding?
Intramolecular bonds, which are strong electrostatic forces formed within a molecule
106
What is metallic bonding?
A type of bonding where valence electrons are loosely held and free to move, creating positive ions surrounded by a sea of electrons.
107
when there is a lone pair on the central atom is the compound polar or non polar?
POLAR
108
What characterizes polar molecules?
Unequal charge distribution, resultant vector does not equal zero, and produces a molecular dipole.
109
What does the delta negative (𝜹-) symbol indicate?
The atom with the higher electronegativity pulls the bonding pair of electrons closer to it.
110
Fill in the blank: The more polar a molecule, the stronger the _______ forces.
dipole-dipole
111
How does the size of an atom or molecule affect London dispersion forces?
The larger the atom or molecule, the stronger the London dispersion force
112
Fill in the blank: Polar molecules produce a molecular _______.
dipole
113
what electronegativity does a small atom with many protons have?
LARGE electronegativity
114
Name the three types of intramolecular bonds.
* Ionic bonds
* Covalent bonds
* Metallic bonds
115
Fill in the blank: The atom with higher electronegativity in a polar covalent bond is ______.
partially negative (𝜹-)
116
What are the two most common allotropes of sulfur and phosphorus?
S8 for sulfur and P4 for phosphorus.
117
What happens to atomic size as you move from left to right across the periodic table?
Size of the atom decreases
## Footnote
Increased nuclear charge pulls electrons closer, reducing atomic radius.
118
How are ionic bonds formed?
Between a metal and a non-metal by electron transfer, resulting in electrostatic attraction.
119
What factors affect the strength of attraction (electronegativity) between charged particles?
Distance between charges and magnitude of the charges
## Footnote
The closer the charges, the stronger the attraction; more charge increases force.
120
What are network solids?
Substances that produce some of the hardest materials on Earth, like diamond
- They involve a large number of atoms covalently bonded in various patterns.
121
What is the trend of electronegativity on the periodic table?
Decreases down a group and increases across a period
## Footnote
This trend is due to atomic structure and electron shielding effects.
122
What is a polar covalent bond?
A covalent bond between two atoms in which the electrons are not shared equally.
123
What characteristic of molecular compounds affects their conductivity?
Molecular compounds form non-conducting solutions due to no free moving charged particles (electrons or ions).
124
What is the role of the central atom in bonding?
It is the one with the largest bonding capacity.
125
What is represented in electron dot diagrams?
The structure and formation of chemical bonds.
126
What are unit cells in the context of crystal lattices?
Smaller repeating patterns that form the crystal lattice.
127
What is the highest electronegativity value and which element has it?
Fluorine (4.0).
- Fluorine's high electronegativity indicates it has the greatest attraction for electrons.
128
Which elements are never found in combination with others?
Noble gases
- Noble gases have full valence shells, making them stable and unreactive.
129
Define an alloy.
An admixture of metals, or a metal combined with one or more other elements
- Alloys often have properties different from their constituent metals.
130
What is the bond pair and lone pair count for a tetrathedral molecule?
Bond pairs: 4
Lone pairs: 0
131
True or False: Diamonds are examples of ionic crystals.
False.
132
What is the first step in determining the total number of valence electrons?
Determine the total number of valence e- and divide by 2 to get electron pairs.
133
What is the octet rule?
Most stable elements need 8 valence electrons to create a stable configuration.
134
What does electronegativity measure?
The ability of an atom in a molecule to draw bonding electrons to itself.
## Footnote
Electronegativity plays a crucial role in determining the nature of chemical bonds.
135
What does the VSEPR theory state?
Molecules adjust their shapes so that the valence electrons are as far away from each other as possible.
136
How can you determine if a molecule is polar or nonpolar?
1. Draw a stereochemical diagram. 2. Determine polarity of each bond. 3. Add bond dipole vectors.
137
What happens in an ionic bond?
The bonding electrons are transferred between the atoms.
138
What is the bond pair and lone pair count for a trigonal planar molecule?
Bond pairs = 3, lone pairs = 0.
139
In VSEPR theory, what does 'A' represent?
The central atom.
140
What causes London dispersion forces?
Momentary (temporary) dipoles created between positive and negative electrons
141
What is a lone pair in terms of electron orbitals?
A full orbital (2 e-) that is not involved in bonding.
142
What factors contribute to the strength of hydrogen bonds?
Size of the atoms involved and extreme difference in electronegativities
143
What is the bond pair and lone pair count for trigonal pyramidal molecule?
Bond pairs: 3
Lone pairs: 1
144
What is a unique characteristic of fluorine in terms of electronegativity?
Small size with many protons results in large electrostatic force
## Footnote
Fluorine is the most electronegative element.
145
If the surrounding atoms of the central atom are different, what type of molecule is it?
Polar.
146
What is the energy needed for vaporization of water?
40.65 kJ/mol
147
What is a crystal lattice?
A large three-dimensional structure formed by ionic solids.
148
How do molecular compounds differ from ionic compounds in structure?
Molecular molecules are finite, unlike large structures composed of repeating patterns in ionic crystal lattices.
149
What do molecular formulas indicate?
Molecular formulas indicate the exact number of atoms bonded together to form the molecule.
150
What is the result of the formation of an ionic compound?
A transfer of electrons that form positive and negative ions with filled energy levels.
151
True or False: Network solids can consist of two different elements.
True
## Footnote
Some network solids are made up of multiple elements.
152
What should be considered when choosing the central atom in a molecular structure?
Choose the atom with the most unpaired electrons as the central atom.
153
What can be used to determine the number of valence electrons?
Ion charge
- for example, Fe 3+ has three valence electrons.
154
What causes the polarity of the water molecule?
Differing electronegativity values of hydrogen and oxygen, along with lone pairs on the oxygen atom.
155
What is the order for boiling points between different bonding types? (Highest boiling point to lowest)
Rank from highest to lowest: Network covalent > Ionic > Metals > Molecular with HB > Molecular with DD > Molecular with LD
156
What do molecular formulas represent?
Molecular formulas represent the actual number of each individual element in the molecule.
157
What is the purpose of placing lone pairs around peripheral atoms?
To satisfy their octet if any are left after bonding pairs are assigned.
158
What are diatomic elements?
Seven elements are diatomic, meaning they exist as two-atom molecules.
159
shape formula of tetrahedra:
AX4
160
shape formula of trigonal pyramidal:
AX3E
161
shape formula of trigonal planar:
AX3
162
shape formula of V shaped/bent:
AX2E2
163
Valence shell elctron-pair repulsion(VSPER) theory:
- states that molecules adjust their shapes so that the valence elctrons are as far away from each other as possible
164
Angles of the stereochemical shapes:
Linear: 180
Trigonal Planar: 120
Tetrahedral: 109.5
165
166
INTERmolecular forces:
- forces between molecules
- weaker than intra
- physical properties
- Hydrogen bonding, London dispersion, Dipole Dipole
167
INTRAmolecular forces:
- forces within a molecule
- stronger
- responsible for chemical properties
- covalent and ionic bonds
168
Chemical vs physical properties:
Physical:
- boiling point
- melting/freezing point
- solubility
- conductivity
Chemical:
- energy change(exo or endothermic)
- odors
- colour change
- formation of gas(bubbles)
- formations of solid(precipitate)
169
what are the examples of network covalent bonds:
C60, C82, C70, SiO2, BC4
170
How to tell Polar vs Non-polar in terms of charges:
- If there is negative dipole **AND** positive dipole on the outside it is **POLAR**
- If there is a negative dipole **OR** a positive dopel on the outside it is **NON POLAR**
171
order of states in terms of strength of intermolecular forces:
least to greatest:
- Gas
- Liquid
- Solid
172
How many valence electrons does boron need to fufill the octet rule?
only 6
173
In what scenario do the charges cancel out to make a non polar compound?
- linear bond formation
- 2 of the same outer molecules
- charges cancel out leaving a nonpolar bond instead of polar
- ie. CO2
174
most polar meaing:
HIGHEST DEN
175
properties of molecular:
- soluable in water
- does not conduct
- melts easily
176
When can you tell the boiling point by amount of electrons?
- ONLY when just London Dispersion forces are precense
- If there is dipole or hydrogen bonding look down groups(decreases as you move down) and at DEN
177
are ionic conductive?
yes, in solution
not by itself
178
Do polar molecules conduct?
NO
179
are ionics soluable in water?
YES
180
structual isomers:
molecules that share the same molecular formula but have different structural arrangements or connectivity of atoms
