Chemistry 2 - Bonding, Structure and Properties of Matter Flashcards
(87 cards)
1
Q
What are ions?
A
Charged particles formed when atoms gain or lose electrons to get a full outer shell.
2
Q
What charge does a metal ion have when it loses electrons?
A
Positive (cation).
3
Q
What charge does a non-metal ion have when it gains electrons?
A
Negative (anion).
4
Q
Group 1 elements forms what ions?
A
1+ ions
5
Q
Group 2 elements forms what ions?
A
2+ ions
6
Q
Group 6 elements form what ions?
A
2- ions
7
Q
Group 7 elements form what ions?
A
1- ions
8
Q
What is ionic bonding?
A
The strong electrostatic attraction between oppositely charged ions.
9
Q
Dot and cross Diagrams
A
10
Q
What type of structure do ionic compounds form?
A
A giant ionic lattice.
11
Q
Why do ionic compounds have high melting and boiling points?
A
Due to many strong electrostatic forces between ions requiring large amounts of energy to break.
12
Q
Can solid ionic compounds conduct electricity? Why or why not?
A
No, because the ions are fixed in place and cannot move.
13
Q
When can ionic compounds conduct electricity?
A
When melted or dissolved in water, because the ions are free to move and carry current.
14
Q
What is an example of an ionic compound and the ions that form it?
A
Sodium chloride (NaCl): Na⁺ and Cl⁻.
15
Q
Finding out the empirical formula in a dot and cross diagram?
A
Count up how many atoms there are of each element and write this down to give you the empirical formula
16
Q
Finding out the empirical formula in a 3D diagram?
A
Drop, swap method
17
Q
What is covalent bonding?
A
Sharing pairs of electrons between non-metal atoms.
18
Q
Atoms only share electrons in their what shell?
A
Outer shell
19
Q
What holds atoms together in a covalent bond?
A
The attraction between the shared electrons and the nuclei of the bonded atoms.
20
Q
Dot and cross diagrams in covalent bonds
A
21
Q
What is a molecule?
A
A group of atoms joined together by covalent bonds.
22
Q
What are simple molecular substances?
A
Substances made of molecules with a few atoms joined by covalent bonds.
23
Q
Name examples of simple molecular substances.
A
Hydrogen (H₂), chlorine (Cl₂), oxygen (O₂), nitrogen (N₂), methane (CH₄), water (H₂O), hydrogen chloride (HCl).
24
Q
Why do simple molecular substances have low melting and boiling points?
A
Because of weak intermolecular forces, which are easily overcome.
25
Do simple molecular substances conduct electricity?
No, because they don’t contain charged particles (no ions or free electrons).
26
What happens to the strength of intermolecular forces as molecules get bigger?
The strength of intermolecular forces increases, so more energy is required to break them, and the melting and boiling points increase.
27
What is a polymer?
Lots of small units are linked together to form a long molecule that has repeating sections and they are joined together by covalent bonds.
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Repeating units in polymers
learn this
29
Why are polymers harder to break apart in comparison to simple covalent molecules?
The intermolecular forces between polymer molecules are larger than between simple covalent molecules, so more energy is required to break them apart.
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Are the intermolecular forces in polymer molecules weaker or stronger than ionic or covalent bonds?
Weaker
31
Do polymer molecules have a higher or lower boiling and melting point than ionic or giant molecular compounds?
Lower
32
What are giant covalent structures?
Where all the atoms are bonded by strong covalent bonds in a lattice structure.
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Why do giant covalent structures have high melting points?
Because lots of energy is needed to break the strong covalent bonds between the atoms.
34
Why do giant covalent structures do not conduct electricity?
They do not contain charged particles.
35
Name three allotropes of carbon.
Diamond, graphite, and graphene.
36
Describe the structure of the diamond.
Each carbon atom forms 4 covalent bonds in a rigid, tetrahedral structure.
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Why is diamond hard?
Due to its strong and rigid covalent bond structure.
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Does diamond conduct electricity?
No, it has no free electrons or ions.
39
Describe the structure of graphite.
Each carbon atom bonds only forms 3 covalent bonds creating sheets of carbon atoms arranged in hexagons.
40
Why is graphite slippery?
Weak forces between layers allow them to slide.
41
Can graphite conduct electricity?
Yes, due to delocalised electrons.
42
What is graphene?
A single layer of graphite, one atom thick.
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Why is graphene strong and light?
It has strong covalent bonds but is only one atom thick.
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Why is graphene a good conductor?
It has delocalised electrons that move freely.
45
What are Fullerenes
Fullerenes are molecules of carbon, shaped like closed tubes or hollow balls.
They’re mainly made up of carbon atoms arranged in hexagons, but can also contain pentagons (rings of five carbon atoms) or heptagons (rings of seven carbon atoms).
Fullerenes can be used to 'cage' other molecules. The fullerene structure forms around another atom or molecule, which is then trapped inside. This could be used to deliver a drug into the body.
Fullerenes have a huge surface area, so they could help make great industrial catalysts — individual catalyst molecules could be attached to the fullerenes. Fullerenes also make great lubricants.
46
What are the three states of matter?
Solid, liquid, and gas.
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What's the first Fullerenes
Buckminsterfullerene was the first fullerene to be discovered.
48
What determines a substance’s state?
How strong the forces of attraction are between the particles.
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What are its physical qualities it?
Nanotubes can conduct both electricity and thermal energy (heat).
They also have a high tensile strength (they don’t break when they’re stretched).
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What kind of technology can be achieved with Fullerenes
Technology that uses very small particles such as nanotubes is called nanotechnology. Nanotubes can be used in electronics or to strengthen materials without adding much weight, such as in tennis racket frames.
51
What type of electrons are involved in metallic bonding?
The electrons in the outer shell of metal atoms are delocalised, meaning they are free to move around rather than being tied to a single atom.
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What holds metal atoms together in metallic bonding?
Strong electrostatic attractions between the positive metal ions and the shared negative delocalised electrons hold the atoms together in a regular structure.
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Why is metallic bonding considered very strong?
Because the forces of attraction between the positive metal ions and the delocalised electrons are very strong, requiring a lot of energy to break.
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Which substances exhibit metallic bonding?
Metallic elements and alloys are held together by metallic bonding.
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What role do delocalised electrons play in metals?
They are responsible for all the characteristic properties of metals, such as conductivity, malleability, and strength.
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Why are most metals solid at room temperature?
Because the electrostatic forces between metal atoms and delocalised electrons are strong and need a lot of energy to break, metals have high melting and boiling points, so they remain solid at room temperature.
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Why are metals good conductors of electricity and heat?
The delocalised electrons carry electrical charge and thermal energy throughout the metal structure efficiently.
58
What does it mean when metals are described as malleable?
It means the layers of metal atoms can slide over each other without breaking the metallic bond, allowing metals to be bent, hammered, or rolled into sheets.
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Why are alloys generally harder than pure metals?
Because mixing different sized atoms into pure metals distorts the regular layers of metal atoms, making it harder for the layers to slide over each other.
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What are alloys made of?
Alloys are mixtures of two or more metals or a metal and another element.
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Why do alloys tend to be more useful than pure metals?
Because alloys are harder and stronger, making them better suited for various practical applications compared to softer pure metals.
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What are the three states of matter?
Solid, liquid, and gas are the three states of matter.
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What determines the state of a substance at a certain temperature?
The state depends on how strong the forces of attraction are between particles, which is influenced by:
a) the material (its structure and bond types),
b) the temperature, and
c) the pressure.
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How does the particle theory model particles in matter?
It treats particles as small, solid, inelastic spheres to explain how they behave in solids, liquids, and gases.
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Describe the forces and arrangement of particles in a solid.
Solids have strong forces of attraction holding particles close in fixed positions, forming a regular lattice. Particles vibrate but don’t move from their positions.
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Why do solids keep a definite shape and volume?
Because the particles are held tightly in place and don’t flow, solids maintain both shape and volume.
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What happens to particles in a solid when heated?
They vibrate more vigorously, causing the solid to expand slightly.
68
Describe the forces and arrangement of particles in a liquid.
Liquids have weak forces of attraction; particles are randomly arranged and free to move past each other but stay close.
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What properties do liquids have regarding shape and volume?
Liquids have a definite volume but no definite shape; they flow to fill the bottom of a container.
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How do particles behave in liquids?
Particles move with random motion, and when heated, they move faster, causing liquids to expand slightly.
71
Describe the forces and arrangement of particles in gases.
Gases have very weak forces of attraction, with particles far apart and free to move in straight lines.
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Do gases have definite shape or volume?
No, gases have no definite shape or volume and will fill any container they’re in.
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How do gas particles move, and what happens when they are heated?
Gas particles move constantly with random motion. When heated, they move faster, causing gases to either expand or increase pressure.
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What is a limitation of the particle theory model?
The model simplifies particles as solid, inelastic spheres and doesn’t show the forces between them, so it can’t indicate the strength of attractions accurately.
75
What do state symbols in chemical equations represent?
State symbols show the physical state of reactants and products:
(s) = solid
(l) = liquid
(g) = gas
(aq) = aqueous (dissolved in water)
76
What does the symbol (aq) mean in a chemical equation?
It means the substance is dissolved in water.
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What happens during a physical change in state?
The particles don’t change, only their arrangement or energy changes.
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What happens to particles in a solid when heated?
They gain energy, vibrate more, and the forces holding the solid weaken.
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What is the name of the process when a solid turns into a liquid?
Melting — occurs at the melting point when particles break free from fixed positions.
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What happens to particles in a liquid when heated?
They gain more energy, move faster, and bonds between particles weaken and break.
81
What is the name of the process when a liquid turns into a gas?
Boiling (or evaporating) — occurs at the boiling point when particles break bonds and become gas.
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What happens to gas particles when cooled?
They lose energy, move slower, and bonds form between them.
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What is condensing?
When gas turns into a liquid because bonds form as the particles lose enough energy.
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What happens to liquid particles when cooled?
They lose energy, move less, and more bonds form between particles.
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What is freezing?
When a liquid becomes a solid as bonds hold particles in fixed positions, occurring at the melting point.
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What determines the amount of energy needed to change state?
The strength of forces between particles. Stronger forces require more energy, leading to higher melting and boiling points.
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