2. Melting and boiling point: giant structures
Substances with giant structures generally have high melting and boiling points because all the atoms are strongly bonded together to form a continuous 3D lattice. A large amount of energy is needed to break these bonds.
strong covalent bonds holds atoms together
strong metallic bonds holds ions together
strong ionic bonds holds ions together

3. Ionic bond=metal and non-metal
The electrostatic attraction between oppositely charged ions
Metal loses electrons to become positive (cation)
Non-metal gains to become negative (anion) 2+ -
ATOM
ATOM Cl Be Cl Be
Be 2,2
Cl 2,8,7
Be2+ [2] 2+
Cl- [2,8,8] -

4. Ionic bonds ALWAYS FORM GIANT IONIC STRUCTURES not molecules
High m.p. and b.p.- lots of strong ionic bonds in the giant ionic lattice, lots of energy to break.
Conducts electricity when dissolved or molten- free moving ions, can conduct (solid= ions in fixed position cannot move)
Soluble in water-water is polar so opposite charges attract ions out of the lattice.

5. Covalent bond=non-metal and non-metal
The electrostatic attraction between a shared pair of electrons and two nuclei
Atoms share up to 3 electron pairs to complete outer shell
Learn dot and cross for, O2, H2, Cl2, H2O, CH4, NH3 , HCl , N2, C2H4, CH3OH and CO2

6. Simple covalent molecules e. g
Simple covalent molecules e.g. O2, H2, Cl2, H2O, CH4, NH3 , HCl , N2, C2H4, CH3OH and CO2
Gases and liquids at room temperature, low m.p. and b.p.- ONLY weak forces of attraction between molecules. Do not conduct – no free ions or electrons

7. Giant covalent structures
Uses
drilling-its very hard
Jewelry-shiny
Uses
pencils-soft and dark (makes a mark on the page)
Lubricant-only weak forces between the layers, can easily slip and slide over each other.

8. Copy: Metal Structure
Definition of a metallic bond -the attraction between the array of positive metal ions and the sea of delocalised electrons.
Why ? All metal atoms are arranged in a regular pattern - Lattice
Metal atoms have tendency to loose electrons to become stable
Delocalised electrons from outer shells of metal
Conduct heat
Conduct electricity

9. Examples of Alloys Different types of steel Steel = IRON + CARBON
= IRON + CARBON + Chromium / Nickel
= IRON + CARBON + Manganese

10. Brass = Copper + Zinc.
Bronze = Copper + Tin
Solder = Zinc + Lead
Amalgam = Mercury + Silver

11. When you hit the metal, the layers can slide….. Metal
force
But for alloys, when you hit, the layers cannot slide…..because the atoms are of different size!!
So More STRONG than metals
force