TOPIC 2 - BONDING, STRUCTURE + PROPERTIES OF MATTER

Question 1

What are the 3 types of strong chemical bonds?

Answer 1

Ionic, Covalent, Metallic

Question 2

In ionic bonding, what’s happening and who’s involved?

Answer 2

• the particles are oppositely charged ions
• formed with metals and metals

Question 3

For covalent bonding, what’s happening and who’s involved?

Answer 3

• the particles are atoms which share pair of electrons
• formed with non-metals and non-metals

Question 4

For metallic bonding, what’s happening and who’s involved?

Answer 4

• particles which share delocalised electrons
• metals and alloys

Question 5

How does chemical bonding involving electrostatic forces work? This is to do with sharing electrons

Answer 5

The metal loses electrons to gain a full outer shell, becoming stable + positively charged ion.
The non-metal gains those electrons to gain a full outer shell, becoming stable + negatively charged ion.
The oppositely charged ions are strongly attracted to each other by electrostatic forces forming the ionic bond

Question 6

What are the characteristics of a giant ionic lattice?

Answer 6

• a giant structure of ions
• held together by strong electrostatic forces of attraction between oppositely charged ions
• the forces are gonna act in all directions of the lattice

Question 7

What are the limitations of dot and cross diagrams?

Answer 7

• don’t represent the 3D structure of molecules
• not suitable for complex molecules

Question 8

What are the limitations of the ball and stick method?

Answer 8

• no representation of electron distribution
• misleading representation of atomic size

Question 9

If u see 1 magnesium ion (Mg2+) and 2 chloride ions (Cl-) : How to find empirical formula of an ionic compound?

Answer 9

1. Ions: Mg and Cl
2. Count: 1 Mg and 2 Cl
3. Ration 1:2
4. Formula MgCl2

Question 10

What are polymers?

Answer 10

Covalent substances that have very large molecules

Question 11

What type of covalent structures are diamond and silicon dioxide?

Answer 11

Giant covalent structure

Question 12

How can we recognise common substances have small molecules from their chemical formulas?

Answer 12

• small number of atoms in their formula
• usually non-metals elements
• simple rations

EXAMPLES:
- H20
- C02

Question 13

What are the 3 states of matter?

Answer 13

Solid, Liquid Gas

Question 15

When does melting and freezing happen?

Answer 15

Melting and freezing take place at the melting point.

Question 16

When does boiling and condensing happen?

Answer 16

Boiling and condensing take place at the boiling point.

Question 17

The amount of energy needed to change state from solid to liquid and from liquid to gas depends on?

Answer 17

Strength of the forces between the particles of the substance

Question 18

What determines how high a substances melting and boiling point is?

Answer 18

The stronger the forces between the particles the higher the melting point and boiling point of the substance.

Question 19

What are the limitations of the particle theory?

Answer 19

• no forces
• particles are represented as spheres
• the spheres are solid

Question 20

What doesn’t have the bulk properties of materials?

Answer 20

Atoms

Question 21

Explain the limitations of the particle theory

Answer 21

• no forces of attraction between particles
• spherical particles
• inelastic collisions

Question 22

What are the 4 symbols to represent solid, liquid, gas and aqueous?

Answer 22

s, l, g, aq

Question 23

Why do ionic compounds have high melting and boiling points?

Answer 23

These compounds have high melting points and high boiling points because of the large amounts of energy needed to break the many strong bonds.

Question 24

If a substance has small molecules, what else does it have?

Answer 24

Substances that consist of small molecules are usually gases or liquids that have relatively low melting points and boiling points.

Question 25

Why do compounds with small molecules have low melting and boiling points?

Answer 25

Weak intermolecular forces which don't take much energy to break.

Question 26

If a substance with small molecules melts, what is overcome and what is not?

Answer 26

The weak intermolecular forces are overcome The covalent bonds are not overcome.

Question 27

The atoms in the polymer molecules are linked to other atoms by?

Answer 27

Strong covalent bonds

Question 28

Why are substances with polymers solid at room temperature?

Answer 28

Because the intermolecular forces between polymer molecules are relatively strong.

Question 29

What does a polymer diagram look like?

Answer 29

A snake of spheres with a line connecting them all

Question 30

If a substance consists of a giant covalent structure, what's its melting point like?

Answer 30

Very high

Question 31

Give 3 examples of giant covalent structures

Answer 31

- diamond - graphite - silicon dioxide

Question 32

Describe the structure of metals and their melting/boiling points

Answer 32

Metals have giant structures of atoms with strong metallic bonding. This means that most metals have high melting and boiling points.

Question 33

In pure metals, why can they be bent and shaped?

Answer 33

In pure metals, atoms are arranged in layers, which allows metals to be bent and shaped.

Question 34

What is an alloy?

Answer 34

An alloy is a mixture of two or more elements, at least one of which is a metal.

Question 35

How are the atoms arranged in an alloy?

Answer 35

Regular pattern of layers, with delocalised electrons able to move between them

Question 36

Why are alloys harder than metals?

Answer 36

There are different sized atoms in alloys which disrupt the regular arrangement of atoms, making it harder for layers to slide increasing resistance to change shape.

Question 37

Why are metals good conductors of electricity?

Answer 37

Metals are good conductors of electricity because the delocalised electrons in the metal carry electrical charge through the metal.

Question 38

Why are metals good conductors of heat?

Answer 38

Metals are good conductors of thermal energy because energy is transferred by the delocalised electrons.

Question 39

In diamond, how many carbon atoms are formed? what type of melting point does it have? does it conduct electricity?

Answer 39

- each carbon forms 4 covalent bonds in a giant covalent structure - high melting point - does not conduct electrcity

Question 40

In graphite, how many covalent bonds and other carbon atoms? Each carbon atom forms what type of rings in between each layer? Do the layers have covalent bonds?

Answer 40

In graphite, each carbon atom forms three covalent bonds with three other carbon atoms. Forming layers of hexagonal rings which have no covalent bonds between the layers.

Question 41

In graphite what happens to one of the electrons from each carbon atom?

Answer 41

They become delocalised

Question 42

Graphite is similar to what? and in what way?

Answer 42

- metals - they both have delocalised electrons

Question 43

Describe the properties of graphene

Answer 43

- high electrical conductivity - high thermal conductivity - high strength Graphene is a single layer meaning delocalised electrons can flow through + strong covalent bonds make it strong and allowing heat to travel through it easily

Question 44

What are fullerenes?

Answer 44

Fullerenes are molecules of carbon atoms with hollow shapes.

Question 45

Describe the structure of fullerenes

Answer 45

Fullerenes are molecules of carbon atoms with hollow shapes.

Question 46

What are carbon nanotubes?

Answer 46

Carbon nanotubes are cylindrical fullerenes. Their properties make them useful for nanotechnology, electronics and materials.

Question 47

Compare the size of atoms and molecules to nano-dimensions

Answer 47

Atoms = 1nm Molecules = 1nm

Question 48

What are the uses of nanoparticles?

Answer 48

- medicine - electronics - cosmetics - catalysts

Question 49

Name 2 advantages of the applications of nanoparticulate materials

Answer 49

- enhanced properties - high surface area to volume ratio - targeted drug delivery`

Question 50

Name 2 disadvantages of the application of nanoparticulate materials

Answer 50

- potential health risks - potential environmental damage