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# Ionic Compounds and Lattice Structure **Ionic compounds:** Have a lattice structure with positive and negative ions held together by strong electrostatic forces of attraction. *High melting/boiling points:* Due to strong electrostatic forces between oppositely charged ions, a lot of energy is req...

# Ionic Compounds and Lattice Structure **Ionic compounds:** Have a lattice structure with positive and negative ions held together by strong electrostatic forces of attraction. *High melting/boiling points:* Due to strong electrostatic forces between oppositely charged ions, a lot of energy is required to break these bonds. *Do they conduct electricity?* In solid state, no, because ions are fixed in place. In molten state (yes) because ions are free to move. # Metallic Structure *Metallic lattice structur:* Giant metal atoms which lose their outer shell electrons which are free to move. *High melting points:* Many strong attractive forces between positive metal ions and a sea of delocalized electrons, thus high energy is required to break these forces. *Good electrical and thermal conductivity:* Delocalized electrons move through the metal structure in both solid and molten state. # Covalent Bonds *Form:* Between non-metal atoms. *How?:* When a pair of electrons is shared between two atoms, this is to complete the outer shell. *Definition:* A covalent bond is a shared pair of electrons between atoms. *Valency:* The number of electrons needed to obtain a complete outer shell. An example given of calculating the valency is H and S giving a formula of H₂S. # Dot and Cross Diagrams *Use:* For covalent bonds. # High Melting Points **Ionic compounds:** High melting points due to strong electrostatic forces between oppositely charged ions which are difficult to overcome. **Metals:** High melting points due to strong attractive forces between positive metal ions and a sea of delocalized electrons. # Malleable and Ductile Metals *Malleable:* Metals can be hammered or pressed into different shapes without shattering. *Ductile:* Metals can be pulled to make wires without breaking. This is due to the ability of the layers of metal ions to slide over each other due to the delocalized electrons.