Structure and Bonding Flashcards

1
Q

Define a compound

A

Two or more elements which are chemically combined

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2
Q

What is the special group of elements that are stable and extremely unreactive?

A

The noble gases

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3
Q

When atoms share electrons what type of bonding is this?

A

Covalent

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4
Q

When atoms permanently give electrons what type of bonding is this?

A

Ionic

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5
Q

In ionic bonding when atoms lose or gain electrons they create particles called __________

A

Ions

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6
Q

During ionic bonding what happens to the protons?

A

There is one more proton in the nucleus than electrons around on the outer shell

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7
Q

When non metals react with metals which one gains electrons and why?

A

The non metal atom gains electrons to get a full outer shell

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8
Q

Which bond is it when a group 7 element steals an electron from a group 1 element?

A

Ionic bond

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9
Q

What does metallic bonding contain

A

a delocalised cloud of electrons

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10
Q

What are delocalised electrons?

A

free electrons

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11
Q

What type of force holds the ions together in an ionic compound?

A

electrostatic forces of attraction

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12
Q

Why do ionic compounds have a high boiling and melting point?

A

They take lots of energy to break up

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13
Q

Why can’t a solid ionic compound conduct electricity?

A

It’s ions are held in a fixed position and can’t move around

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14
Q

What force is between molecules in covalent bonding?

A

intermolecular forces

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15
Q

What are diamond and silicone both examples of?

A

strong covalent structures

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16
Q

Give three properties of strong covalent structures

A

Hard
High melting and boiling points
Insoluble in water

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17
Q

Why do the layers in Graphite slide over so easily?

A

There are weak intermolecular forces between they layers

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18
Q

What can we make with chemicals from crude oil?

A

polymers

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19
Q

What joins together to make polymers?

A

monomers

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20
Q

What do the properties of a polymer depend on?

A

The monomers used

The conditions chosen

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21
Q

What types of two polyethene are there?

A

HD and LD (Density)

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22
Q

Why are both types of polyethene different?

A

They are made in different conditions

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23
Q

How is a low density polyethene formed? (2 Marks)

A

With Lots of pressure (1 mark) and some oxygen ethene forms polyethene (1 mark)

24
Q

How is a high density polyethene formed? (2 Marks)

A

With a catalyst at 50 degrees and a slightly raised pressure ethene forms polyethene

25
Q

What are thermosoftening polymers?

A

Polymers that soften quite easily and reset when they cool down

26
Q

What are thermosetting polymers?

A

Polymers that do not melt when we heat them

27
Q

Which polymer has strong covalent bonds?

A

thermosetting polymers

28
Q

Give two risks of nanoscience

A
  1. Their large surface area makes them good catalysts

2. Using them too much could result in them being in the air.

29
Q

What group do ions have the structure of?

A

Noble gases

30
Q

When halogens react with alkalis what is formed?

A

Ionic compounds

31
Q

When halogens react with alkalis, what charge do the halide ions have?

A

A single negative charge

32
Q

Name two covalent structures.

A

Diamond and silicone dioxide

33
Q

What are electrons in the outer shell of a metal atom?

A

Delocalised

34
Q

If electrons are delocalised what does this mean?

A

They’re free to move

35
Q

What are some substances that consist of simple molecules?

A

Gases, solids and liquids with low boiling and melting points

36
Q

What kind of force do substances with simple molecules have?

A

Intermolecular forces (weak forces)

37
Q

When a substance boils or melts, what is overcome? The covalent bond or the intermolecular forces?

A

The intermolecular forces

38
Q

Why don’t substances that consist of simple molecules conduct electricity?

A

The molecules do not have an overall charge

39
Q

What kind of melting and boiling point to ionic structures have?

A

High melting and boiling point

40
Q

Can ionic compounds conduct electricity when melted or under water? If yes, why?

A

Yes they can, the ions are free to move and can carry the current

41
Q

What kind of melting point does a covalent bond have?

A

A high melting point

42
Q

In diamond how many covalent bonds are formed?

A

4 bonds with other carbon atoms

43
Q

What makes diamond so strong?

A

The 4 covalent bonds with other carbon atoms that it has

44
Q

In graphite each carbon bonds to…

A

3 other carbon

45
Q

In graphite when carbon bonds to three others what does this form?

A

Layers

46
Q

Why can the layers slide over each other in a covalent structure?

A

Because there are no covalent bonds between the layers so graphite is soft and slippery

47
Q

In graphite what is different about each carbon atom?

A

One electron from each carbon atom is delocalised

48
Q

What do the delocalised electrons in graphite help with?

A

Conduct heat and electricity

49
Q

What can carbon form with different numbers of carbon atoms?

A

Fullerenes

50
Q

Give 4 things fullerenes can be used for?

A
  • Drug delivery
  • Lubricants
  • Catalysts
  • Nanotubes
51
Q

Why can metals be bent and shaped?

A

Because the layers of atoms in metals are able to slide over each other

52
Q

Why are alloys harder than pure metals?

A

The different sized atoms of the metals
distort the layers in the structure, making it more
difficult for them to slide over each other

53
Q

What can shape memory alloys do after being deformed?

A

Return to their normal shape

54
Q

What do Thermosoftening polymers consist of?

A

Individual tangled polymer chains

55
Q

Why don’t thermosetting polymers melt when heated?

A

They have polymer chains with cross-links between

them to prevent melting