Bonding, Structure & Properties of Matter

What are the changes in matter

Describe the bonding of ionic compounds (sodium chloride)

• sodium loses one electron to become positively charged

• The electron is transferred to chlorine

• Both elements have a full outer shell

• An ionic bond is formed

Explain why sodium chloride has a high melting and boiling point

• bonded by strong electrostatic forces

• Take a lot of energy to overcome the forces

Describe the bonding of covalent molecules (carbon dioxide)

• carbon shares 4 electrons with oxygen

• Oxygen shares 2 electrons each

• Oxygen and carbon now have a full outer shell

Explain why CO2 has a low melting and boiling point

• molecules are held together by weak intermolecular forces

• Low amount of energy to break these bonds

What is the structure and bonding of ionic compounds

• bonded by strong ionic bonds

• Electrostatic forces

• Giant lattice structure

• Solid at room temp

• High boiling & melting point

• conducts electricity at only molten or dissolved

Explain why ionic compounds can only conduct electricity when in a molten or dissolved state

• Ions can move through the structure

• Carrying a charge

• Due to being surrounded by a sea of electrons

Define polymer

A long chain of repeating molecules

What is polymerisation?

• when molecules combine to form a polymer

What is a monomer?

A single unit of a polymer

State four different monomers and their polymer

1. ethene → polyethene

2. propene→ polypropene

3. Styrene → polystyrene

4. Chloroethene → polychloroethene

Describe the forces of attraction between polymers

• relatively strong

• Molecules are larger then simple molecules

• Require more energy to overcome

• Solids at room temp

Describe the formation of diamond

• made up of carbon atoms

• Each carbon atom is bonded by 4 other carbon atoms

• Strong covalent bond

• Lot of energy to overcome bonds

• Solids at room temp

• Cannot conduct electricity

• tetrahedron shape

Explain why diamond has a high melting and boiling point

• held together by strong covalent bonds

Takes a lot of energy to overcome these bonds

Explain why graphite is softer then diamond

• hexagonal rings in layers

• Layers move over each other

Explain why graphite can conduct electricity

• Weak forces of attraction allows the layers to move

• graphite has delocalised electrons

• The layers move allowing the electrons to carry an electrical charge

Explain what graphene is

a layer of graphite

Describe a Fullerene

• hallow sphered

• Cage other molecules

• Held together by strong covalent bonds

State some usages of fullerenes

• deliver drugs into the body

• Trapping medicine

• Nanotubes when in a cylindrical shape

What are the properties of metals

• conductor of electricity n thermal energy

• Malleable (can be bent easily into shape)

• Ductile

What is meant by a pure metal?

Made up of 1 type of metal atom

Explain why pure metals are soft

• all the atoms are the same size

• Arranged in a regular pattern

• Layers of atoms can easily slide over each other

What is an alloy?

Mixture of different metal atoms

Why would adding another substance to copper (a metal) make copper harder?

• Atoms will have different sizes

• Distorts the regular pattern Mates

• More difficult for layers to slide over each other