Structure & Bonding of Carbon Flashcards
All 19 cards in this deck
How many covalent bonds does each carbon atom form in diamond?
Four covalent bonds, with four other carbon atoms.
What type of structure does diamond have?
A giant covalent structure (a giant covalent lattice / macromolecular structure) of carbon atoms.
Why is diamond very hard?
Its carbon atoms are joined by many strong covalent bonds in a rigid giant lattice.
Why does diamond have a very high melting point?
Its covalent bonds are strong and many of them must be broken, so a lot of energy is required.
Why does diamond not conduct electricity?
It has no delocalised electrons — all the outer electrons of each carbon atom are used in covalent bonds, so it has no charged particles free to move.
True or false? In diamond, one electron from each carbon atom is delocalised.
False. In diamond all four outer electrons of each carbon are used in covalent bonds; it is graphite that has one delocalised electron per carbon atom.
How many covalent bonds does each carbon atom form in graphite?
Three covalent bonds, with three other carbon atoms.
How are the carbon atoms arranged in graphite?
In layers of hexagonal rings, with no covalent bonds between the layers.
How many electrons from each carbon atom are delocalised in graphite?
One electron from each carbon atom is delocalised.
Why does graphite conduct electricity?
One delocalised electron per carbon atom is free to move through the structure, carrying charge.
Why is graphite soft and slippery?
There are no covalent bonds between the layers, so the layers can slide over each other.
True or false? Graphite is similar to metals in that it has delocalised electrons.
True. Both graphite and metals have delocalised electrons, so both conduct electricity and thermal energy.
What is graphene?
A single layer of graphite — a sheet of carbon atoms in hexagonal rings, one atom thick.
Which properties of graphene make it useful in electronics and composites?
It conducts electricity (delocalised electrons) and is very strong for its very low mass.
What are fullerenes?
Molecules of carbon atoms with hollow shapes, based on hexagonal rings but they may also contain rings of five or seven carbon atoms.
Which fullerene was the first to be discovered, and what shape is its molecule?
Buckminsterfullerene, — it is spherical (ball-shaped).
What is a carbon nanotube?
A cylindrical fullerene with a very high length to diameter ratio, useful in nanotechnology, electronics and materials.
Give two uses of fullerenes.
Any two from: drug delivery round the body, lubricants, catalysts, hydrogen storage, strengthening materials (nanotubes).
True or false? Fullerenes are made only from hexagonal rings of carbon atoms.
False. Their structure is based on hexagonal rings, but they may also contain rings of five or seven carbon atoms.