Bonding- C2

• Different atomic forms of the same element 
• The same number of protons
• Different number of neutrons

Atoms of 2 or more elements chemically combined together

• Giant ionic lattices
• Ions form a closely packed regular lattice arrangement
• Strong electrostatic forces of attraction between the oppositely charged ions in all directions

• High melting+ boiling points
• Strong attraction between the ions
• Takes a large amount of energy to overcome this attraction
• When ionic compounds melt, the ions are free to move+ carry electric current
• Ionic compounds dissolve easily in water
• Ions separate+ are free to move in the solution-> carry the current 

• Ions have the electronic structure of a noble gas
• The overall charge of any compound is 0

• Having a full outer shell gives atoms an electronic structre of a noble gas
• Covalent bond is shown by a line

• Strong covalent bonds between atoms
• Small molecules
• Weak intermolecular forces of attraction
• Low m.p.+ b.p.
• Molecules are easily parted from each other
• Intermolecular forces get broken when substances change state
• Most of these substances are gases/ liquis at room t, but can be solids
• Don't conduct electricity- no ions-> no electrical charge

• Macromolecules
• All the atoms bonded to each other by strong covalent bonds
• High m.p.+ b.p.
• Don't conduct electricity

Diamond:

• Each carbon atom forms 4 covalent bonds
• Rigid giant covalent structure

Graphite:

• Each carbon atom forms 3 covalent bonds
• Layers slide over each other
• Soft+ slippery
• The layers are held together so loosely-> can be rubbed off due to weak intermolecular forces between the layers
• Good conductor of heat+ electricity
• Each carbon atom has a delocalised electron
• Free electrons conduct heat+ electricity

• Giant structure
• Free delocalised electrons come from the outer shell of every metal atom in the structure
• These electrons move through the whole structure-> good conductors of heat+ electricity
• Electrons hold the atoms together in a regular structure
• Strong forces of electrostatic attraction between the positive metal ions+ the negative electrons
• Electrons allow the layers of atoms to slide over each other, allowing metals to be bent+ shaped

• Alloys are harder than pure metals
• They have different elements with different sized atoms
• New metal atoms distort the layers of metal atoms-> more difficult for them to slide over each other