Metallic bonding
What is metallic bonding?
electrostatic attraction between positive metal cations and a delocalised sea of electrons
occurs in preu metals and metal alloys
Outermost electron of metal atoms are free to move throughout the structure
Metals loose their outer electrons (forming positive ions - cations)
Strong electrostaic attraction between cations and electrons hold metal together → explains properties
non directional
Describe the structure of metallic bonding.
Explain how metallic bonding contributes to the properties of metals.
Electrial conductivity → Valence electrons in metals form a mobile sea of electrons that carry charge.
Thermal conductivity → movement of delocalised elctrons allow heat to transfer quickly
Malleble and ductile → bonding between metal ions and free electrons is non-directional, allowing atoms to slide without breaking.
Shiny appearance → Free electrons reflect light
High melting point & boling point → Strong electrostatic attraction requires high energy to break
Alloys mixture of metals (or metals with non metals) to enhance properties
e.g Brass (copper + zinc) stronger and more corrosion-resistant than pure copper
Stainless steel (iron + carbon + chromium) more durable and resistant to rust
Alloys contain different-sized atoms that distort the metal lattice, making it harder for layers to slide and increasing strength.
Applications
Electricial wiring → Copper is used because of its excellent conductivity.
Contrsuction materials → Steel is strong and durable, used in buildings and bridges.
Jewellery → Gold alloys improve strength while maintaining appearance.
Aerospace → Aluminium alloys are lightweight and corrosion-resistant.
Compare metallic bonding with ionic bonding