together.
Giant Structures - ANSWER Metals have giant structures of regularly arranged
atoms in a lattice.
Delocalised Electrons - ANSWER Delocalised electrons from the outer shells are
free to move throughout the structure.
Electrostatic Forces - ANSWER The strong electrostatic forces of attraction
between the positive metal ions and the delocalised electrons form the metallic
bonds.
Electrical Conductivity - ANSWER Delocalised electrons carry electrical charge
through the structure.
Thermal Conductivity - ANSWER Delocalised electrons and closely packed ions
transfer energy through vibrations.
Malleability - ANSWER Malleable - Can be hammered into shapes.
Ductility - ANSWER Ductile - Can be drawn into wires.
High Melting & Boiling Points - ANSWER Large amounts of energy are needed to
break the strong metallic bonds.
Ionic Bond - ANSWER Strong electrostatic forces between oppositely charged ions
form the ionic bond.
Ion - ANSWER An ion is a charged particle that forms when atoms gain or lose
electrons.
Positive Ion (Cation) - ANSWER More protons than electrons.
Negative Ion (Anion) - ANSWER More electrons than protons.
Sodium Chloride (NaCl) - ANSWER Sodium loses 1 electron → Na⁺; Chlorine gains
1 electron → Cl⁻.
Lithium Oxide (Li₂O) - ANSWER Lithium loses 1 electron → Li⁺; Oxygen gains 2
electrons → O²⁻.
, High Melting & Boiling Points (Ionic Compounds) - ANSWER Strong electrostatic
forces of attraction require a lot of energy to break.
Electrical Conductivity (Ionic Compounds) - ANSWER Solids - Do not conduct
electricity (ions are fixed). Molten/Dissolved in water - Conducts electricity (ions are
free to move and carry charge).
Covalent Bonding - ANSWER Occurs between two non-metal atoms.
Shared Electrons - ANSWER Electrons are shared to give each atom a full outer
shell.
Single Covalent Bond - ANSWER Chlorine (Cl₂) → Cl-Cl.
Double Covalent Bond - ANSWER Oxygen (O₂) → O=O; Carbon dioxide (CO₂) →
O=C=O.
Giant Ionic Structures - ANSWER Ionic compounds form giant lattice structures
with strong electrostatic forces in all directions.
Properties of Giant Ionic Structures - ANSWER High melting & boiling points -
Strong ionic bonds require lots of energy to break.
Simple Molecular Structures - ANSWER Consist of small molecules held together
by weak intermolecular forces.
Properties of Simple Molecular Structures - ANSWER Low melting & boiling points -
Weak intermolecular forces require little energy to break.
Giant Covalent Structures - ANSWER Contain thousands of atoms bonded in a
giant network with strong covalent bonds.
Properties of Giant Covalent Structures - ANSWER Very high melting & boiling
points - Many strong covalent bonds need lots of energy to break.
Allotropes of Carbon - ANSWER Diamond: Each carbon bonds to 4 others →
Strong covalent lattice.
Diamond - ANSWER Extremely hard → Used in drill bits & cutting tools.
Extremely hard - ANSWER Used in drill bits & cutting tools.
Does not conduct electricity - ANSWER No delocalised electrons.
, Graphite - ANSWER Each carbon bonds to 3 others, forming hexagonal layers.
Conducts electricity - ANSWER Delocalised electrons between layers carry charge.
Soft and slippery - ANSWER Layers slide over each other → Used in pencils &
lubricants.
Graphene - ANSWER Single layer of graphite (one atom thick).
Graphene properties - ANSWER Extremely strong but lightweight.
Graphene conductivity - ANSWER Conducts electricity better than graphite.
Metallic bonding - ANSWER Example: Cu, Fe, Al; ✔ Conducts (delocalized
electrons); High melting & boiling points; Malleable & Ductile.
Ionic bonding - ANSWER Example: NaCl, MgO; ✔ When molten/dissolved; High
melting & boiling points; Brittle.
Covalent (Simple) bonding - ANSWER Example: H₂O, CO₂; ✘ No free electrons;
Low melting & boiling points; Weak intermolecular forces.
Covalent (Giant) bonding - ANSWER Example: Diamond, SiO₂; ✘ Except Graphite;
Very High melting & boiling points; Hard & Strong.
Indicators - ANSWER Substances that change colour when added to acids or
alkalis.
Litmus - ANSWER A common indicator: Red in acids, Blue in alkalis.
Universal Indicator - ANSWER Provides a more precise pH measurement by
changing colour according to pH level.
pH Scale - ANSWER Acidity/Alkalinity measured from 0 to 14.
Strong acid - ANSWER pH 0 - 3; Colour in Universal Indicator: Red.
Weak acid - ANSWER pH 4 - 6; Colour in Universal Indicator: Orange/Yellow.
Neutral - ANSWER pH 7; Colour in Universal Indicator: Green.