Bonding Flashcards
(121 cards)
1
Q
Define Metallic Bonding
A
The electrostatic force of attraction between a lattice of positively charged ions (cations) and a sea of free-moving, ‘delocalised’ electrons
2
Q
What are some several common properties of metals?
A
-Good conductors of electricity when solid or liquid
-Good conductors of heat
-Malleable and Ductile
-Usually solid at room temp, with high melting and boiling points
3
Q
What does malleable mean?
A
Can be beaten into sheets
4
Q
What does ductile mean?
A
Can be drawn into wires
5
Q
The electrons are negatively charged and moving in metallic bonding so they can….
A
-can transfer electrical charge
-can transmit thermal energy (heat)
-can move to adapt to new shapes formed by the metal cations
6
Q
Metals are good conductors of electricity due to…..
A
Sea of delocalized electrons in the lattice which can carry and transfer electrical charge
7
Q
Metals are good conductors of heat due to…
A
THE KINETIC ENERGY OF CATIONS (VIBRATIONS) AND ELECTRONS (MOVEMENT) IS PASSED EFFICIENTLY THROUGH THE METAL.
Sea of delocalized electrons in the lattice can transmit thermal energy (heat)
8
Q
Metals are malleable and ductile due to….
A
The fact that layers of cations can slide past each other relatively easily, while delocalised electrons can move to maintain electrostatic attraction.
9
Q
Metals generally have high melting and boiling points due to…
A
The strong electrostatic force of attraction between positive nuclei and sea of delocalised electrons requires a lot of energy to overcome
10
Q
What can’t we explain using the metallic bonding model?
A
-The range of melting points, hardness, electrical conductivity and densities - especially in d-block elements such as mercury compared to gold
-The magnetic properties of elements such as iron, cobalt and nickel
11
Q
Besides the main properties, what are some other common metallic properties?
A
Lustre, Sonorous, Low 1st Ionisation energy and electronegativity
12
Q
Explain Lustre as a common metallic property
A
Lustre is the way light reacts with the surface of a crystal, rock or mineral. Metals are described at lustrous (shiny) This is due to delocalised electrons forming a barrier to reflect the light from the metallic surface
13
Q
Explain Sonorous as a common metallic property
A
Metals are sonorous in that they can resonate and enable sound to be produced. This is why many instruments are made from brass or related alloys.
14
Q
Explain low 1st Ionisation and electronegativity as a common metallic property
A
Metals are found on the left of the periodic table and have lower core charge than non-metals of similar size. this results in a low first ionisation energy and a low electronegativity
15
Q
Link reactivity complexity to contract
A
The more reactive a metal, the more complex method required to contract
16
Q
What does ‘native’ mean in relation to metals?
A
combined
17
Q
What is an alloy?
A
Mixture of two or more metal elements
18
Q
Metal + Oxygen >
A
Metal Oxide
19
Q
Metal + Acid >
A
Salt + Hydrogen
20
Q
Metal + Water >
A
Metal Hydroxide + Hydrogen
21
Q
Metal + Steam >
A
Metal Oxide + Hydrogen
22
Q
What is a circular economy?
A
It is one where the resources from a product are returned back into the economy which is a close product cycle.
23
Q
What is a linear economy?
A
It is when a product is essentially disposed of in landfill (or equivalent) after it has been used
24
Q
What is the purpose of a circular economy?
A
It seeks to reduce environmental impacts of production and consumption while using resources more productively and creating less waste.
25
What process is used to produce iron from its ore and to produce aluminum from its ore?
IRON = Displacement reactions (using carbon in a blast furnace)
ALLUMINIUM = Electrolysis; using graphite electrodes
26
Lead formula
Pb2+
27
Tin formula
Sn2+ or 4+
28
Zinc formula
Zn2+
29
Silver formula
Ag+
30
Iron formula
Fe2+ or Fe3+
31
Copper formula
Cu+ or Cu2+
32
Accetate (ethanoate) formula
CH2COO-
33
Nitrate formula
NO3-
34
Hydroxide formula
OH-
35
Permanganate formula
MnO4-
36
Cyanide formula
CN
37
Sulfate formula
SO42-
38
Carbonate formula
CO32-
39
Chromate formula
CrO42-
40
Dichromate formula
Cr2O72-
41
Phosphate formula
PO43-
42
Ammonium formula
NH4+
43
Name the Ionic Bonding Model and what each word means
It is a Giant Ionic Lattice consisting of a regular, repeating 3D structure of alternating cations and anions.
GIANT = THE ACTUAL NUMBER OF PARTICLES IS UNDERFINED
IONIC = THE PARTICLES ARE IONS
LATTICE = THE STRUCTURE IS REGULAR AND REPEATING
44
What are some common physical properties of ionic substances?
High MP and BP, Hard, Brittle, Non-conductive (electrically and thermally) as solids, conduct electricity as liquids or in solution
45
Why does Ionic Bonding have a high MP and BP?
The strong electrostatic force or attraction between oppositely charged ions requires a lot of energy to overcome.
46
When are electrostatic forces of attraction stronger in ionic bonding?
If the charge on the ions is greater or if the ions can get closer to each other
47
Why does Ionic Bonding result in ionic compounds being brittle?
Because when a strong enough force is applied to the giant ionic lattice which is regular and repeating, a layer of the lattice may shift causing repulsion between the layers and the crystal splits or shatters = BRITTLE
48
Why does Ionic Bonding electrically conductive? (SOLID/LIQUID)
SOLID - the ions are held together in a crystalline lattice. the ions are not free to move as there are no free moving charged particles so NOT electrically conductive
LIQUID/DISSOLVED - there are free ions to move through the structure so the liquid or solution is electrically conductive
49
Why does Ionic Bonding mean hard to dissolve?
In any ionic crystal, some ions will be exposed at the surface. These ions are susceptible to attractions from other substances including solvents such as water. Because water is a polar molecule, it has a negative pole so is attracted to positive ions and a positive pole which is attracted to negative ions, This attraction is called an ion-dipole force. If the attraction between water and the ions is similar to or greater than the attraction between the ions themselves, the ionic compound will be soluble in water, COMPOUNDS WITH STRONG FORCES BETWEEN IONS ARE GENERALLY HARDER TO DISSOLVE
50
Summarise how substances dissolve in water (ionic compounds)
The forces being formed need to be approximately the same strength or stronger than the forces being broken in order for dissolution/dissociation to occur.
forces broken between ions in the ionic compound and forces broken between water particles >>> ION DIPOLE FORCES FORMED BETWEEN IONS AND WATER MOLECULES
51
If an ionic compound has ions in different sizes, what does it mean in relation to force?
The attractive forces between the ions are relatively weak because they cannot pack closely together
52
If an ionic compound has ions in of similar sizes, what does it mean in relation to force?
The attractive forces between the ions are relatively strong because they can pack closely together
53
Which compound is likely to be more soluble and why; a compound with ions of very different sizes or similar sizes?
Ones with ions of different sizes are forces being broken are weaker
54
What are the ions not involved in a precipitation reaction called?
Spectator ions
55
Define Ionic Bonding
The strong electrostatic force of attraction between oppositely charged ions
56
What is a molecule?
Made of two or more non-metal atoms
57
Define covalent bonding
The electrostatic force of attraction between two atomic nuclei and a shared pair of electrons between those atoms
58
Are single, double or triple bonds stronger?
Triple bonds are stronger than double bonds
Double bonds are stronger than single bonds
59
What is a dative bond?
A dative covalent bond is one in which BOTH of the shared electrons are contributed by one atom only
60
When is a dative bond established between two atoms?
a) One of the two atoms has a full outer shell including a non-bonding pair of electrons
b) The other atom is one pair short of a full outer shell of electrons
61
What is in a valence structure?
Lines show bonds
Lone pairs as dots
62
What is in a lewis structure (electron dot diagram)?
Shows all bonds as dots as well as outer electrons as dots
63
Why do we care about molecular shape?
The shape of a simple covalent molecule affects the melting point, boiling point, hardness and solubility of that substance
64
If it has 2 electrons groupings what is the electron geometry and what are the possible molecule shapes?
LINEAR
Linear = no lone pairs
Diatomic = one lone pair
65
If it has 3 electrons groupings what is the electron geometry and what are the possible molecule shapes?
TRIGONAL PLANAR
Trigonal planar = no lone pairs
Bent = one lone pair
Diatomic = two lone pairs
66
If it has 4 electrons groupings what is the electron geometry and what are the possible molecule shapes?
TETRAHEDRAL
Tetrahedral = no lone pairs
Trigonal pyramidal = one lone pair
Bent = two lone pairs
Diatomic = three lone pairs
67
Explain trigonal pyramidal and planar shape
pyramidal = lone pair at top, bond at 3, 6 and 9 o'clock
planar = 12, 5 and 7 o'clock
68
What are polar molecules?
They have an uneven distribution of charge. They always have a positive side (pole) and a negative side (pole) so are also called dipoles.
69
What needs to occur for a molecule to be polar?
1. There must be polar bonds present
2. The polar bonds must be arranged assymetrically (so they do not cancel out each others polarity!)
70
What are intramolecular forces and some examples?
It is an umbrella term of bonding that occurs within elements and compounds. e.g covalent, metallic, ionic
71
What are the two types of covalent substances?
1. Simple covalent molecules (substances that are made of non-metal atoms and have a known molecular formula that describes the number of atoms per molecule e.g CO2)
2. Giant covalent networds (covalent networks are non-metal substances that exist as giant, 3D arrays of atoms. e.g graphite, diamond, silicon dioxide)
72
Simple covalent substances generally....
-have low MP AND BP
-doesn't conduct electricity
-soluble in water only when polar
73
Why do simple covalent substances not conduct electricity?
As their valence electrons are fixed in place, they have no free movement of charged particles to carry charge
74
Giant covalent networks generally...
-Have high MP AND BP
-insoluble in water
-does not conduct electricity (except graphite) and conducts heat poorly
-very hard substances (except graphite)
-insoluble in water
75
Explain diamond's structure
Giant network of carbon atoms, each carbon atom is covalently bonded to four others in a tetrahedral arrangement, strong covalent bonds between atoms
76
Explain graphite's structure
Another allotrope (strucutral formula) of carbon. It has a high melting point, insoluble in water, an undefined number of atoms
BUT unlike diamond...
-it is soft
-it conducts electricity
each C is joined to 3 others with the 'spare' electron being delocalised
77
Are intermolecular or intramolecular forces stronger?
INTRAMOLECULAR FORCES ARE ALL STRONGER THAN THE INTERMOLECULAR FORCES
78
What is it that determines the physical properties of a simple covalent substance?
Intermolecular forces NOT covalent bonds
79
List intermolecular forces from weakest to strongest
Dispersion forces > Dipole-Dipole forces > Hydrogen bonding
80
What is another name for dispersion forces?
Instantaneous dipole-induced dipole forces
81
Briefly explain dispersion forces
Occurs between all molecules (due to constant movement of electrons which gives rise to electrostatic forces of attraction), weak in comparison to other forces, the more electrons in a sample, the stronger the dispersion forces (since temporary dipole can form more easily), the bigger the molecule of the sample, the stronger the dispersion forces between the molecules because there is greater surface area
82
How do you know when one has greater forces than another?
Greater electrons!!
but if they have the same number of electrons, then it follows the rules of
the more branches in a molecule, the more spherical it comes therefore, SA decreases and this decreases strength of forces
83
Briefly explain dipole-dipole forces
Involves polar molecules. Polar molecules have a permanently uneven distribution of charge. They always contain polar bonds which are arranged assymetrically.
84
Which are stronger and why; dispersion or dipole-dipole forces?
Dipole-dipole forces because they require more energy/force to overcome
85
What is hydrogen bonding?
An extra strong type of dipole-dipole force that occurs between molecules bonded to a NOF and attracted to the lone pair of a NOF on a neighbouring molecule.
86
What are dispersion forces between?
An instantaneous and an induced dipole
87
What are dipole-dipole forces between?
Permanent dipoles
88
Two non-polar molecules =
Dispersion forces
89
One non-polar molecule and one polar =
Dispersion forces
90
Two polar molecules =
Dipole-Dipole forces
91
Polar molecules, involving NOF-H---NOF =
Hydrogen Bonding
92
What do we call when the two substances after dissolving are both liquids?
We say that they are miscilble
93
What is dissolving?
Dissolving is when one substance is pulled apart by another, or moves into the spaces between another and is referred to as the process of dissolution
94
What is solubility?
The extent to which a solute can dissolve in a solvent
95
What does the 'like dissolves like' principle mean?
If both the solvent and solute particles contain charged regions, or if neither do, it is likely that the solute will dissolve.
96
Simple explanation of the process of dissolving
forces broken between solvent particles and forces broken between solute particles > forces formed between solvent and solute particles
97
If a substance dissolves...
-forces between solute particles have been overcome
-forces between solvent particles have been overcome
-new forces of attraction are formed between solvent and solute particles
THE FORCES FORMED NEED TO BE APPROXIMATELY THE SAME STRENGTH OR STRONGER THAN THE FORCES BEING BROKEN IN ORDER FOR DISSOLUTION TO OCCUR
98
Consider dissolving of octane in water
Dispersion forces broken between octane molecules
Hydrogen bonds broken between water molecules
Dispersion forces formed between octane and water molecules.
THE BONDS BEING FORMED ARE WEAKER THAN THOSE THAT WERE BROKEN. THEREFORE OCTANE IS INSOLUBLE IN WATER
99
Polar molecules form what with water?
Hydrogen bonding or dipole-dipole attractions (depending if a 'NOF' group is present)
100
What do molecules that ions react with water?
Some molecules react with water to form ions and then form ion-dipole forces with the water molecules
101
How do ionic compounds react with water?
Ionic compounds which dissolve dissociate into ions which forms ion-dipole bonds with the water molecules in the solvent. negative ions attracted to delta positive H atoms and positive ions attracted to delta negative O atoms
102
Chromatography is a technique where...
Used to separate mixtures into their individual components based on differences in how they move through a medium.
103
Now what's the simple explanation of chomtography?
Chromatography separates substances based on how well they "stick" to a surface (the stationary phase) versus how well they dissolve and move with a solvent (the mobile phase).
104
What are some examples of when chromatography is used?
-drugs present in blood
-sugars in fruit juice
-hydrocarbons in oil
-food dyes in sweet
105
What are the two phases that all methods of chromatography have?
Stationary phase = a solid or liquid the sample is applied to
Mobile phase (moving phase) = a liquid or gaseous phase that is passed through or over the sample
106
Explain chromatography
In the mixture to be separated, each substance is carried along by the mobile phase (usually a liquid or gas), and interacts with the stationary phase (a solid or viscous liquid). Those substances that are most strongly adsorbed to the stationary phase will move more slowly, while those less strongly adsorbed will move faster, resulting in separation.
107
What are the three components in chromatography?
So who’s who?
🧪 The mixture = what you're trying to separate (e.g., different dyes in black ink)
💧 Mobile phase = the solvent or gas that moves and carries the mixture
📄 Stationary phase = the surface the mobile phase moves over (e.g., filter paper)
108
Name all the phases when ink is tested using chromatography
You place a dot of black ink (the mixture to be separated) on filter paper.
You dip the bottom of the paper in water.
The water is the mobile phase.
As the water rises, it carries the ink up the paper.
The ink separates into different colored dyes based on how strongly each one:
Dissolves in the water (mobile phase)
Sticks to the paper (stationary phase)
✨ TL;DR:
The mixture is what you want to separate
The mobile phase is what carries it
The separation happens because different parts of the mixture move at different speeds
109
What does stronger absorption mean in relation to chromatography?
Strong adsorption to the paper = the substance sticks more = moves slower > closer to origin
110
What does weaker absorption mean in relation to chromatography?
Weaker adsorption = the substance moves with the mobile phase more easily = travels further up the paper > further from origin
111
Important things in paper tomography
-baseline needs to be drawn in pencil 1-2cm away from bottom of the paper
-measure from centre of spot
112
In paper chromatography, how do i know whether it's an element, compound or mixture as original sample?
2 splotches = mixture
1 splotch = element or compound
113
What is Rf and what is it used for?
It is the retention factor. It is simply a value used to compare the different compounds in the mixture.
114
What does a higher Rf value mean?
The greater solubility/attraction in the mobile phase
115
What does a lower Rf mean?
The stronger attraction in the mobile phase.
116
How to calculate Rf?
distance spot moved/distance solvent moved
technically a ration between component and solvent
117
How to calculate 'new movement' in application questions for paper chromatography when it says solvent front has moved 18.6cm opposed to 10.5cm?
..../10.5 = 0.92 x 18.6 = 17.2cm
118
How to know which bond is the most polar?
the greater the electronegativity difference, the more polar the bond is!
119
What does diatomic mean?
Two atoms
120
Examples of diatomic molecules
Hydrogen (H₂)
Nitrogen (N₂)
Oxygen (O₂)
Fluorine (F₂)
Chlorine (Cl₂)
Bromine (Br₂)
Iodine (I₂)
121
