Lesson 2 : Bonding, structure and properties of Matter

Ion

A charged particle

Ionic bond

Bonding between a metal and a non-metal

Structure of an ionic compound

Giant lattice of oppositely charged ions

What holds an ionic bond together?

An electrostatic attraction between oppositely charged ions

Properties of ionic compounds

1. High melting/Boiling points

2. Brittle (will snap)

3. Conducts electricity as a liquid/ when dissolved in water but doesn't as a solid

Why do ionic compounds have high melting and boiling points?

The strong electrostatic forces of attraction between oppositely charged ions takes a lot of energy to overcome

Why do some ionic compounds have higher melting/ boiling points than others?

The higher the charge on the ions the stronger the attraction between them

Why can ionic compounds conduct electricity when they are liquids or dissolved in water, but not when they are solid?

1. AS A SOLID:

Ions are in fixed positions and are therefore unable to move around, and cannot carry electrical charge

2. AS A LIQUID:

Ions are able to move around when the compound is in liquid state, and therfore carry electrical charge

Why are ionic compounds brittle?

They are brittle because applying a force shifts the alternating ion layers, placing ions with the same charge next to each other, which creates strong repulsive forces that shatter the lattice

Metallic bond

Bonding, usually in solid metals

Structure of metallic bonding

Layers of positively charged ions, closely packed together in a sea of delocalised electrons

What holds a metallic bond together?

A strong electrostatic attraction between all the positive ions and the delocalised electrons

Properties of metallic bonding

1. High Melting/boiling point

2. Malleable and ductile

3. Conduct electricity

4. When they are mixed with other elements they form alloys

Why do metals have high melting and boiling points?

There are very strong electrostatic forces of attraction between the positively charged metal ions and the negatively charged delocalised electrons

Why can metals conduct electricity?

The delocalised electrons are free to move throughout the structure and can carry charge

Why are metals malleable?

The layers of ions can slide over each other

Why are alloys harder than pure metals?

the different sized atoms of the metals distort the organised layers of the structure, resulting in layers being unable to slide over each other

Covalent bond

A bond between two non-metals

Structure of a covalent bond

1. Simple molecular

2. Giant lattice

What holds a covalent bond together?

An electrostatic attraction between the positively charged nuclei and negatively charged shared pair of electrons

Properties of a simple molecular structure

1. Low melting/boiling points

2. Doesn't conduct electricity at all

Why do simple molecular substances have low melting and boiling points?

Molecules are held together by strong covalent bonds, but deforested molecules are held together by weak intermolecular forces of attraction that take only a little energy to overcome

Why don't simple molecular substances conduct electricity at all?

There are no charges particles able to move around (no delocalised electrons or ions)

Allotropes of carbon

1. Diamond

2. Graphite

3. Graphene

4. Buckministerfullerene

Structure of diamond

Giant lattice

How many bonds does each carbon atom form?

4 covalent bonds

Properties of diamond

1. High melting point

2. Hard

3. Does not conduct electricity at all

4. Good conductors of heat

Why does diamond have a high melting point?

There are strong covalent bonds between atoms that take a lot of energy to overcome

Why is diamond hard?

There are strong covalent bonds between atoms that take a lot of energy to overcome

Why does diamond not conduct electricity?

No delocalised electrons or ions

Why is diamond a good conductor of heat?

Heat can travel fast through the structure as all atoms are connected

Uses of diamond

1. Coatings on the ends of tools

2. Jewellery

Structure of graphite

Giant lattice

How many bonds does each carbon atom form?

3

What holds graphite together?

The carbon atoms in each layer are joined together by strong covalent bonds but layers or carbon atoms are held together by weak intermolecular forces of attraction

Properties of graphite

1. High melting point

2. Soft

3. Does conduct electricity

Why does graphite have a high melting point?

Carbon atoms are held together by strong covalent bonds which take a lot of energy to overcome

Why is graphite soft and slippery?

Layers are held together by weak intermolecular forces of attraction, and can therfore slide over each other

Why does graphite conduct electricity?

Each carbon gain only forms 3 bonds with its neighbours, and therfore the fourth electron in each atom of delocalised and is free to move around and carry electrical charge throughout the structure

Uses of graphite

Pencils and industrial lubricants

What is graphene?

A sheet of graphite

Uses of Graphene

Nanotubes

Structure of buckministerfullerene

Simple molecular structure

What is the formula of buckministerfullerene?

C60

What holds buckministerfullerene together?

Atoms inside molecules are held together by strong covalent bonds but molecules are held together by weak intermolecular forces of attraction

How many bonds does each carbon atom form?

3

Properties of buckministerfullerene

1. Low melting point

2. Not as hard as diamond

3. Does not conduct electricity

Why does buckministerfullerene have a low melting point?

Molecules are held together by weak intermolecular forces of attraction which do not take a lot of energy to overcome

Why is buckministerfullerene not as hard as diamond?

Only the weak intermolecular forces between molecules must be broken

Why dues buckministerfullerene not conduct electricity?

Even though carbon only firms 3 bonds, the delocalised electron is only free to move around its molecule, and therfore cannot carry charge throughout the structure

Uses of buckministerfullerene

1. Transport drugs in medicines

2. Lubricants

3. Catalysts

Structure for answering allotropes property questions

1. Structure

2. Bonding

3. Property

What is a nano particle?

Any particle that is between 1-100nm in size

How to calculate SA to V ratio

Surface area of shape / volume of shape

Uses of nano-particles

1. Self cleaning glass

2. Suncreams

3. Cosmetics

4. Medicines

Disadvantages of nano particles

1. High surface area makes them dangerous when being used as catalysts (spark could cause explosion)

2. Could damage lungs if breathed in

3. Nano size increases potential toxicity