CC6 +7 Covalent and metallic bonding Flashcards
Explain why chlorine and fluorine form covalent bonds
They are both non-metals
Complete the sentence: In covalent bonds, atoms _________ ________ ___ _________.
atoms share pairs of electrons
What is the name given to the structure of diamond, graphite and silicon dioxide?
Giant covalent
How many bonds does each carbon have in diamond?
4
Explain why diamond has a high melting point
Giant structure, Strong covalent bonds between the atoms, requires a lot of energy to break
Explain why most giant covalent substances do not conduct electricity (3 marks)
There are no electrons or ions/charged particles that are free to move
Explain why graphite conducts electricity
Has delocalised electrons between the layers that can move through the graphite
Explain why graphite can act as a lubricant
Weak forces between layers which are free to slide over each other
What is graphene?
One layer of graphite
What is a fullerene?
Substance made of carbon atoms arranged in a cage
What type of substance are methane and water?
Simple molecular (or simple molecules)
What is a molecule?
A group of atoms chemically bonded together
Describe the structure of simple covalent molecules
Strong covalent bonds between atoms, weak intermolecular forces holding the molecules together
What are intermolecular forces?
Weak forces between molecules which hold them together
Explain why methane has a low melting point
It is a simple molecular substance with weak forces between the molecules (which are easy to break)
What is a polymer?
A long chain molecule formed by many monomers chemically joined
Describe the main features of metals in terms of their structure
Positive metal ions arranged in layers with delocalised electrons
Explain why metals can conduct electricity
Delocalised electrons are free to carry charge
Explain why pure metals are soft and malleable
Layers of metal ions are free to slide over each other
What are the limitations of dot and cross diagrams.
It does not show the shape of the molecule or the size of the atoms.
If a compound name ends in -ate what does this show?
It is a molecule made of the other elements in the name and oxygen.
What are the limitations of a ball and stick model
It does not show the electrons involved in the bonds. It does not show the 3d shape
