Types of Substance - Paper 1 Flashcards
When can a substance conduct electricity?
When charged particles can move freely within the substance.
Describe the structure and bonding of diamond.
- Each carbon atom is joined to 4 others by covalent bonds.
- The carbon atoms form a regular tetrahedral structure.
- There are no free electrons.
Describe uses for diamond.
Diamond is useful for cutting tools, such as diamond-tipped glass cutters and oil rig drills.
Describe the structure and bonding of graphite.
- Each carbon atom is joined to 3 others by covalent bonds.
- The carbon atoms in each layer form a regular hexagonal structure.
- The layers have weak forces between them and can slide over each other.
- Each carbon atom provides one delocalised electron.
Describe uses for graphite.
Graphite can conduct electricity so is useful for electrodes in batteries and for electrolysis.
Sliding layers makes graphite slippery, so it is useful as a lubricant.
How does graphene differ from graphite?
Graphene is a single layer of the structure of graphite.
Graphene has a very high melting point and is very strong because of its large regular arrangement of carbon atoms joined by covalent bonds.
Describe the properties of nanotubes in terms of structure and bonding.
A nanotube resembles a layer of graphene, rolled into a tube shape. Nanotubes have high tensile strength, so they are strong in tension and resist being stretched. Like graphene, nanotubes are strong and conduct electricity because they have delocalised electrons.
Describe the properties of Buckyballs in terms of structure and bonding.
Buckyballs are spheres or squashed spheres of carbon atoms. They are made up of large molecules so are not classed as giant covalent networks. Weak intermolecular forces exist between buckyballs. These need little energy to overcome, so substances consisting of buckyballs are slippery and have lower melting points than graphite or diamond.
What is Buckminsterfullerene?
Buckminsterfullerene is a Buckyball with 60 carbon atoms.
List the typical properties of metals.
- Shiny
- High melting points
- Good conductors of electricity
- Good conductors of heat
- High density
- Malleable
List the typical properties of non-metals.
- Dull
- Low melting points
- Poor conductors of electricity
- Poor conductors of heat
- Low density
- Brittle
Describe the structure and bonding of metals.
In metals, the electrons leave the outer shells of metal atoms, forming positive metal ions and a ‘sea’ of delocalised electrons. The structure of a solid metal consists of closely packed metal ions, arranged in a regular way to form a metallic lattice structure. Metallic bonding is the strong electrostatic force of attraction between the metal ions and the delocalised electrons.
What would the ideal model for structure and bonding show?
- Elements present
- Charges
- Physical shape/structure
- Relative sizes
- Nature of bonds
