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Chemistry > topic 7- structures (inc ionic, giant covalent, simple covalent, polymers and metals) > Flashcards

topic 7- structures (inc ionic, giant covalent, simple covalent, polymers and metals) Flashcards

1
Q

Features of giant covalent structures

A
  • high melting point
  • no specific formula
  • 1 large molecule
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2
Q

Ball and stick diagrams

(i) this component represents bonds between atoms
(ii) this component represents atoms

A

(i) stick

(ii) ball

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3
Q

Why do giant covalent structure ps have very high melting points?

A

As they have very strong covalent bonds between the atoms

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4
Q

Why is diamond hard?

A

It has lots of strong covalent bonds

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5
Q

Why doesn’t diamond conduct electricity?

A

It has no delocalised electrons in its structure

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6
Q

Why does diamond have a high melting point?

A

A lot of energy is needed to break the strong covalent bonds. Therefore it has a high melting point

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7
Q

In diamond, each carbon atom is bonded to __ other carbon atoms by strong covalent bonds

A

4

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8
Q

What is carbon?

A

A giant covalent structure

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9
Q

What shape are the carbon atoms in graphite’s layers?

A

Hexagonal (6-sided)

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10
Q

Graphite has ____ intermolecular forces keeping layers together

A

Weak

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11
Q

Why is graphite very soft?

A

It’s layers can easily slide over one and another

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12
Q

In graphite, each carbon atom is bonded to __ other carbon atoms by strong covalent bonds

A

3

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13
Q

Why can graphite conduct electricity?

A
  • each carbon atoms forms three bonds
  • this means that there is a delocalised electron from every carbon atom
  • this electron can move freely, therefore graphite is a good electrical conductor
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14
Q

What are fullerenes?

A

Molecules of carbon atoms that take up hollow structures. Their structure is usually carbon atoms arranged in hexagonal (6-sided) rings, but pentagonal (5-sided) and heptagonal (7-sided) carbon rings can also be found.

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15
Q

What type of molecule is buckminsterfullerene?

A

A simple molecule because of its fixed size

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16
Q

What shape is the buckminsterfullerene?

A

Spherical

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17
Q

What is the formula for buckminsterfullerene?

A

C60

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18
Q

Common uses of spherical fullerenes:

A
  • catalysts
  • lubricants
  • as vehicles for transporting drugs into our bodies
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19
Q

Carbon nanotubes are…

A

Cylindrical fullerenes

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20
Q

Why are carbon nanotubes exceptionally strong for their size?

A

because of strong covalent bonds between carbon atoms

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21
Q

uses of cylindrical fullerenes:

A
  • in electronics
  • in nanotechnology
  • for strengthening materials (e.g. tennis racket frames)
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22
Q

Carbon nanotubes are often called molecular wires, why?

A

As they have a tiny diameter but can be incredibly long

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23
Q

Why does graphene conduct electricity?

A

Graphene is a single layer of graphite so it also conducts electricity because of the carbon atoms’ delocalised electrons

24
Q

Why is graphene light?

A

It has a thickness of just 1 atom. This means it’s almost a two dimensional structure and so graphene is very light

25
Q

Why is graphene very strong?

A

It has strong covalent bonds between carbon atoms

26
Q

What are graphene’s uses?

A

Graphene has lots of uses in electronics and composite materials
>graphene makes materials stronger without making them much heavier
>graphene can be used in solar panels, batteries and so much more

27
Q

What are polymers?

A

Large chain-like molecules that can extend for thousands of atoms.

28
Q

Polymers are held together by…

A
  • weak intermolecular forces between molecules

- strong covalent bonds between atoms in molecules

29
Q

What state are polymers usually at room temperature?

A

Solid

30
Q

Why do the intermolecular forces in polymers add up to be quite strong?

A

Because of the large size of polymer molecules

31
Q

Why do many polymers melt easily?

A

The intermolecular forces between molecules remain less strong than chemical bonds

32
Q

What does the ‘n’ in the bottom right of a polymer diagram tell us?

A

How many times the unit is repeated to create the larger polymer molecule

33
Q

When polymers undergo addition ____, poly(propene) is the product

A

-polymerisation

34
Q

Why are pure metals soft and malleable?

A

Because the ions are arranged in layers, they easily move over each other when a force is applied

35
Q

Why do pure metals have high melting and boiling points?

A

There are strong electrostatic forces between metal ions and delocalised electrons

36
Q

What are metals made up of?

A

Giant structures of regularly arranged atoms

37
Q

What is the structure of pure metals?

A

A regular lattice of positive ions, cations, in a ‘sea’ of delocalised electrons

38
Q

Delocalised electrons are…

A

-not bound to an atom and are free to move around within the lattice

39
Q

When does delocalisation happen?

A

When metal atoms have a small amount of electrons in their outer shells

40
Q

Which would a metallic bonding be found in:

  • sodium (Na)
  • sodium chloride (NaCl)
A

-sodium (Na)

41
Q

Why are metals good conductors of electricity and heat?

A

Because their delocalised electrons can carry a charge/ heat throughout the structure. The electrons move from the negative terminal to the positive terminal

42
Q

Which bonds have 2 atoms sharing 1 or more pairs of electrons and are found in most non-metal compounds?

A

Covalent

43
Q

Which bonds involve an attraction between positive ions and negative, delocalised electrons

A

Metallic

44
Q

What is an ionic bond formed from?

A

An attraction between a negatively charged ion (anion) and a positively charged ion (cation)

45
Q

What forces hold together an ionic lattice?

A

Electrostatic forces

46
Q

What is the empirical formula of C7H4O2?

A

C7H4O2

47
Q

What type of bonding involves the movement of electrons from one atom to another?

A

Ionic

48
Q

What is happening during freezing?

A

Molecules are losing energy, moving around less and forming a fixed lattice

49
Q

Which of these is a property of ionic compounds:

(i) can conduct electricity while solid
(ii) cannot conduct electricity when molten
(iii) have high melting points

A

(iii) have high melting points

50
Q

which molecule has a higher boiling point:

(i) chlorine
(ii) sucrose

A

(ii) sucrose

51
Q

Which of the following can conduct electricity?

  • NaCl(aq)
  • diamond
  • polythene
  • graphite
A

-NaCl(aq) and Graphite

52
Q

What is the charge on a carbonate ion?

A

2-

53
Q

How many double bonds and single bonds are there in a carbonate ion?

A

Number of single bonds= 2

Number of double bonds= 1

54
Q

Why do electrons become delocalised in metals?

A

Because the electron orbitals in the metal atoms overlap

55
Q

Displacement reactions

A

When a more reactive metal (one that forms positive ions more easily) can displace a less reactive metal from a compound

Chemistry (25 decks)

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