Structure and bonding Flashcards Preview

Ashley Reyes Chemistry > Structure and bonding > Flashcards

Flashcards in Structure and bonding Deck (49):
1

What is ionic bonding?

A strong electrostatic attraction between the positive and negative ions.

2

Where does ionic bonding occur?

It occurs between a metal and a non-metal.

3

What structure does an ion make?

An alternating structure where each ion is surrounded by ions of the opposite charge.
An ionic lattice.

4

Overall the ionic compound is ________.

Neutral.

5

The formula which shows the ratio between the ions is called the ________.

Empiricle formula or Ionic Formula.

6

Properties of Ionic Compounds:

Hard, Brittle
High melting and boiling point (solid at room temp)
Conducts electricity when in a solution

7

Give the ionic formula for: Potassium iodide

KI

8

Give the ionic formula for: Barium Chloride

BaCl2

9

Give the ionic formula: Copper Oxide

Cu2O2 = CuO

10

Give the ionic formula for: Aluminium sulphide

Al2S3

11

Give the ionic formula for: Calcium Sulphate

CaSo4

12

Where does covalent bonding occur?

In non-metal elements and compounds.

13

What happens to electrons in covalent bonding?

They share electrons to get full outer shells.
Each pair is a single covalent bond.

14

Drawing covalent compound rules:

The outer shell should overlap and the shared pair of electrons should be inside the overlap bit.
Only draw the outer shell.
Use dots and crosses to show where the electron originated.

15

Compound for Sulphate:

SO4 (charge -2)

16

Compound for Nitrate:

NO3 (charge -)

17

Compound for Hydroxide:

OH (charge -)

18

Compound for Carbonate:

CO3 (charge -2)

19

Ways to draw Covalent bonds:

Dot Cross diagram
Line diagram

20

What are covalent molecules and their properties?

1. They have low melting and boiling points - they are gases or liquids at room temperature.

2. The bigger the molecules the stronger the forces, so melting and boiling points increase with size.

3. Simple covalent molecules have no overall charge therefore can't conduct electricity.

21

Silicon dioxide:

Large number of strong covalent bonds
High melting and boiling points
Hard Crystalline structure
No charged particles so can't conduct electricity

22

Polymers:

Large molecules made up of repeating units bonded together as long chains
They are represented by showing the individual unit (monomer) and 'n' to represent a large number
e.g. poly (ethane)
The don't conduct electricity

23

Diamond;

Tetrahedral
Each Carbon connected to 4 others
Very hard
High melting and boiling points
Don't conduct electricity as there are no delocalised electrons
Use them as jewels and for cutting stuff as it is really hard.

24

What is a delocalised electron?

An electron that can wander around.

25

Graphite:

Hexagonal structure with many layers.
Quite soft as layers can slide.
High melting and boiling point
Conducts electricity as there is one delocalised electron from each carbon, free to move.
Uses: Lubricant, Pencils

26

Fullerenes:

60 Carbon atoms joined together
To form a ball/tube
Other forms exist like carbon nanotubes
They Conduct electricity as they have delocalised electrons.
Strong
High melting and boiling points
They can be used for drug delivery.

27

Graphene:

A single layer of graphite
It is used in composite materials because the covalent bonds within the layer makes it very strong but flexible as it is so thin
It can conduct electricity.

28

Compound for Ammonium:

NH4 (charge +)

29

Metals have _____.

Layers.

30

What is the structure of a giant metallic lattice?

Electrons from outer shells of metal atoms are free to move.
Positive metal ions

31

Metal atoms ____ outer electrons.

Metal atoms LOSE outer electrons.

32

Metal atoms become ________ ions.

Metal atoms become POSITIVE ions.

33

Free electrons are called ___________ electrons.

Free electrons are called DELOCALISED electrons.

34

The delocalised electrons are ____ to ____ throughout the metallic structure.

The delocalised electrons are FREE to MOVE throughout the metallic structure.

35

There is a strong force of attraction between the _________ ions and the ________ electrons. This is called the _____________ force of __________. This force is very ______ in metals.

There is a strong force of attraction between the POSITIVE ions and the NEGATIVE electrons. This is called the ELECTROSTATIC force of ATTRACTION. This force is very STRONG in metals.

36

Metallic properties because of delocalised electrons:

Can conduct heat and electricity

37

Metallic properties because of layers of metal ions which can slip over each other:

Malleable (Can be shaped)
Ductile (Can be stretched into wires)

38

Metallic properties because of the strong force of attraction between the metal ion and the delocalised electron:

Hard
High melting and boiling point (except mercury - Hg)
Solid at room temperature (except mercury - Hg)

39

What is an alloy?

Mixtures of metals or of a metal and a carbon.

40

Properties of an alloy in comparison to the metals they contain:

They are stronger, harder , less malleable and less ductile than the metals they contain.

41

What do alloys disrupt?

They disrupt the layers, making it harder for them to slide over each other. This is because the atoms are different sizes.

42

Ionic bonding and covalent bonding gives them the structure of :

A noble gas. This makes them very stable.

43

How do you work out the ratio of surface area to volume ratio:

surface area / volume

44

Nanoparticle diameter :

Between 1nm (1 x 10 to the power of -9 m) and 100nm (1 x 10 to the power of -7 m)
These are particles containing only a few hundred atoms.

45

The surface area of a nanoparticle is very _____ in comparison to the ______.

The surface area of a nanoparticle is very LARGE in comparison to the VOLUME.

46

Because nanoparticles have a huge surface area to volume ratio, they could help to make ___ _________.

Because nanoparticles have a huge surface area to volume ratio, they could help to make new catalysts.

47

Nanomedicine:

Tiny particles (such as fullerenes) are absorbed more easily by the body than most particles. This means the could deliver drugs right into the cells where they are needed.

48

Silver nanoparticles:

They have antibacterial properties. They can be added to polymer fibres that are then used to make surgical masks and wound dressings.

49

Nanoparticles in sun creams:

They have been shown to be better at protecting skin from harmful UV rays and give better skin coverage compared to traditional sun creams. It is unclear if they may damage cells and there is a possibility it may damage the environment when washed away.