✅ Flashcards

1
Q

What is it called when atoms share electrons

A

Covalent bonding

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2
Q

What is it called when atoms transfer electrons?

A

Ionic bonding?

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3
Q

What arrangement is formed when ionic bonding occurs?

A

Giant structure/ giant lattice

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4
Q

Characteristics of ionic compounds

A

High melting points

Conduct electricity

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5
Q

Characteristics of simple molecules

A

Weak intermolecular forces

Can’t carry electricity

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6
Q

Why can graphite conduct electricity

A

Delocalised electrons carry charge

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7
Q

What are fullerenes?

A

Hollow shapes molecules of carbon

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8
Q

Uses of fullerenes

A

Transport of drugs
Catalysts
Reinforcement

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9
Q

What is graphene?

A

I atom thick graphite

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10
Q

What is metallic bonding?

A

When the negative electrons hold the positive nuclei in position

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11
Q

What is an alloy?

A

Mixture of two elements, at least one of which is metal

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12
Q

Why can metals bend?

A

The layers slide over eachother

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13
Q

Why do nano particles have different properties?

A

Large SA to volume ratio

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14
Q

Uses of nano particles

A

Sun cream
Glass
Cosmetics

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15
Q

what is it called when a solid changes directly to a gas?

A

sublimation

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16
Q

what is a compound?

A

something that contains two or more elements chemically combined

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17
Q

when elecctrons have been gained what is the charge of the ion?

A

negative

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18
Q

what arrangement do ionic bonds give?

A

giant lattice

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19
Q

why do lattices have such high boiling points?

A

the ionic bonds act in all directions on an atom

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20
Q

why will molten or dissolved ionic compounds conduct electricity

A

ions free to move

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21
Q

What are the three states of matter

A

Solid
Liquid
Gas

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22
Q

Characteristics of particles in solid

A

Packed closely together

Vibrate in fixed positions

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23
Q

Characteristic of liquid

A

Close together but can slide around

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24
Q

Characteristics of gas

A

Lots of empty space of particles to move around

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25
What energy changes happen when something melts or boils?
Energy is transferred to the substance
26
Limitations of the simple particle model
Atoms aren't all solid spheres with no forces between them
27
Why do different substances have different melting points
Depends on the strength of the bonds between them
28
What is covalent
When two atoms share electrons
29
What is ionic bonding?
When atoms transfer electrons to each other and become ions
30
How do ionic compounds stay together.
The forces of attraction between the oppositely charges ions
31
What is formed with ionic bonds
A giant structure or giant lattice
32
Why do ionic compounds have such high melting and boiling points?
The strong electrostatic forces of attraction
33
How to work out the charge of an ionic compound
Look at the charges of the ions | Th overall charge must be 0, so there must be enough of each to cancel out
34
Why will ionic compounds only conduct electricity when dissolved or molten?
The ions become mobile and can carry the charge through the liquid
35
What are covalent bonds?
The strong bonds between atoms that are sharing electrons
36
What is a macromolecule
A giant covalent structure
37
Ho do a shared pair of electrons bond the atoms together?
The positive nuclei are attracted to the negative pair of electrons
38
What are the three ways of representing covalent bonding
``` Dot and cross Displayed formula (single lines show bonds) The 3D model ```
39
Why is it easy to break apart a simple molecular compound (why does it have a lot m and b point)
Weak intermolecular forces
40
Why don’t molecular compounds conduct electricity?
They aren’t charged so there are no free electrons
41
What is a polymer?
A long chain made up of smaller molecules
42
Why does diamond have such a high melting point
Very strong intermolecular forces (bonds to four different atoms)
43
What are intermolecular forces?
The forces between the covalently bonded molecules
44
Why do macromolecules have such a high melting point
All the atoms are bonded to eachother by strong covalent bonds
45
Why can layers in graphite slide off eachother
Weak intermolecular forces
46
What are delocalised electrons
Spare electrons that don’t belong to an atoms so can move through out graphite
47
Why does graphite conduct electricity
Delocalised electrons
48
What is a fullerene?
A large hollow cage made of carbon
49
How many carbon atoms are in a fullerene
60
50
What are carbon nanotubes
Cylindrical fullerenes
51
What is graphene?
A single layer of carbon atoms
52
Three uses of fullerenes
Can ‘cage’ other molecules Deliver drugs Catalyst
53
What type of bonding occurs in metals?
Metallic bonding
54
How are metallic bonds so strong?
The positive metal ions are attracted to the negative delocalised electrons
55
What is an alloy?
A mixture of two elements, at least one of which is a metal
56
Why are metals solid at room temperature?
Strong electrostatic bonds
57
Why are metals good conductors of electricity and heat
Delocalised electrons carry charge and energy
58
Why are metals malleable
Layers of atoms can slide over eachother
59
Why are alloys harder than normal metals
The different sizes atoms mean it’s harder for the layers to slide over eachother
60
What is a nanoparticle?
A very small particle
61
What is important about nanoparticles
Large surface area to volume ratio
62
What is the size range for a nanoparticle
Between 10-9 and 10-7 metres
63
Uses of nanoparticle
Catalysts Nanomedicine (magic bullet) Suncreans Cosmetics
64
Risks of nanoparticle
Large surface area = flammable Breathing them in could damage bloodstream Affecting environment
65
What are nanowires
Very small wires used in electronic circuit
66
What are silve nanoparticles used for
Inhibit growth of microorganism Textiles Sanitation (silver ions protect against bacteria)
67
How are nanocages used to deliver drugs
Can get into the leaky walls of tumours and carry drugs at same time