GCSE - Chemistry - C2 Structure and Bonding

C2 - Structure and Bonding

Ionic bonding is the giving and recieving of electrons to get a full outer shell. Ions are charged, must be drawn in brackets and dots and crosses represent the change in electrons. Ionic compounds are neutral.

Properties

• Do not conduct electricity - ions don't have free moving electrons
• High melting and boiling points - strong electrostatic attraction
• Cuboid shap - one single crystal
• Conducts electricity when dissolved in water or when in moltern state

Covalent bonding is the sharing of electrons between non metals to get a full outer shell. Shells are drawn overlapped for the elctrons shared to be in the middle. Dots and crosses needed.

Properties

• Low melting and boiling points - weak intermolecular forces (strong covalent boinds stay together
• Do not conduct electricity - no free moving electrons.
• Intermolecular forces get stronger the bigger the molecule.

Properties

• one of the hardest materials known - strong covalent bonds
• tetrahedrial - each electron has 4 bonds
• high melting and boiling point - strong covalent bonds
• lustrous and colourless
• doesn't conduct electricity - no free moving electrons

Properties

• can conduct electricity - 1 free moving electron per carbon atom
• layers of hexagonal sheets
• high melting and boiling points - strong covalent bonds (weak intermoleculer forces between layers break easily)

Graphene

• One layer of graphite - no intermoleculer forces
• stronger than diamond - strong covalent bonds
• can conduct electricity - free moving electrons

Buckminsterfullerene

• sphericle graphene
• adminsters dangerous drugs e.g. cancer treatment

Nanotubes

• rolled up graphene - large surface area to volume ratio
• catalysts

Nanoscience - structures 1-100 nanometres in size

Nanometre - 1 billionth of a metre (10 to the power of -9)

Large surface area to volume ratio

Silver 

• kills bacteria - treats burns and disinfecting water
• expensive
• unknown environmental damage

Titanium Dioxide

• whitener in toothpaster, paints, skimmed milk and medicines
• disperses static charges
• scatter UV light - can damage DNA when it reacts

Silica

• waterproof and stainproof coating
• makes liquids create beads that roll off the surface
• most effective on polyester

Alloys are a mixture of 2 or more elemts and 1 is a meta. Most alloys are mixtures of metals 

Alloys layers can't slide over each other because of different sized atoms so they are generally harder and stronger than pure metals