Many are insoluable, but are soluable as they can form intermolecular forces with water that are stronger than those between water and those between themselves
Examples of simple molecular compounds
Water, methane, ammonia
Why do giant covalent structures have very high melting points?
Atoms in the structure are linked to other atoms by strong covalent bonds which require lots of energy to break.
Can giant covalent structures conduct electricity?
Some can
What state are simple molecular forces at room temp?
Gaseous
As you go down group 7 the atoms (and thus molecules) get bigger. This means there will be more intermolecular forces, and so more energy (and a higher temperature) will be required to break them.
Why don't giant molecular structures have weak intermolecular forces?
there is only one structure
Graphite and diamond are different forms of carbon
Graphite and diamond are forms of giant covalent substances
What is an allotrope?
Different structural forms of the same element in the same physical state.
How many carbon atoms are bonded to eachother in a diamond?
Each carbon atom is covalently bonded to 4 other carbon atoms
What is the maximum number of carbon atoms a carbon atom can bond with?
4
Why is diamond strong and why does it have a high melting point?
In the regular 3D lattice, the covalent bonds between the carbon atoms are very strong.
Why doesn't diamond conduct electricity?
It has no free ions or electrons that can move around.
Why is graphite able to conduct electricity and heat?
it is able to bond with up to 4 carbon atoms but only bonds with 3 leaving a spare electron which becomes delocalised and can move freely, and so is able to carry charge.
Why is graphite softer than diamond?
The 2D layers in graphite are stacked on top of eachother with weak intermolecular forces so layers are able to move over eachother making it softer and easier to break.
Why is graphite used to make electrodes?
Graphite has one delocalised electron and can therefore conduct electricity unlike unlike diamond.
Why is graphite used to make lubricants?
It has weak intermolecular forces and no covalent bonds so layers can slide over eachother, and therefore is soft and slipper
Why is diamond used for cutting tools?
Rigid structure makes it very hard
What are the properties of graphene?
It is a single layer of graphite with strong covalent bonds.
What do the properties of graphene make it useful in?