C3 Structure and bonding

• metals loose electrons to form positive ions
• non-metals gain electrons to form negative ions
• group 1 ions always have a +1 charge
• group 2 ions always have a +2
• group 3 ions always have a +3 charge
• group 5 ions always have a -3 charge
• group 6 ions always have a -2 charge
• Group 7 ions have a -1 charge
• Because ions are charged they attract each other by an electrostatic force
• Ionic compounds form giant ionic lattice
• giant lattices are made of repeating positive and negative ions in all three dimensions
• Ionic compounds have high melting points because of a lot of heat energy is needed to break the strong electrostatic forces between oppositely charged ions
• Ionic compounds only conduct electricity when they are molten or dissolved in a solution because the ions must be free to move around to carry a charge
• Covalent bonding happens when non metals react with each other and electrons are shared between the atoms so they all have a full outer shell
• One pair of bonding electrons = single covalent bond
• Simple covalent molecules consist of a set number of atoms and have weak intermolecular bonds between the molecules
• Intermolecular forces are between molecules
• Intramolecular forces are between atoms (covalent bonds)
• Simple covalent molecules do not conduct electricity because they don’t have delocalised electrons
• giant covalent structures consist of an infinite number of atoms covalently joined together
• Giant covalent structures have a very high melting point because of the strong covalent bonds
• Giant covalent structures do not have delocalised electrons
• carbon can exist as a nano particle called fullerene
• Carbon can exist as the giant structures graphite and diamond
• diamond is extremely hard and used for cutting tools
• In diamond each carbon atom forms 4 strong covalent bonds forming a giant covalent structure
• Diamonds have a tetrahedral structure
• In graphite each carbon forms 3 covalent bonds which allows for one electron from each carbon to be delocalised so it conducts electricity
• Graphite is a flat layered structure with weak intermolecular forces so its soft and slippery
• Graphene is a single sheet of carbon atoms from graphite
• Graphene is a conductor and has a low density and is the most reactive type of carbon
• The buckminsterfullerene is a carbon molecule made from 60 carbon atoms
• Nanoparticles are useful as catalysts because they have a high SA
• fullerenes are allotropes of carbon
• Fullerenes have a high melting point
• Carbon nanotubes have high tensile strength therefore they are often used to reinforce items
• carbon nanotubes are used in electronic devices
• Carbon nanotubes cab conduct heat and electricity because they have a similar structure to graphite
• Metals have high melting points due to strong attraction between positive ions and electrons
• Metals are conductors because the electrons are free to move