Metallic Bonding Lecture Notes

Question-and-Answer flashcards covering definitions, structure, bond formation, factors affecting bond strength, and physical properties explained by metallic bonding.

What is metallic bonding?

It is the electrostatic attraction between positive metal ions and a sea of delocalised electrons in a giant metallic lattice.

Describe the structure of a metal.

A regular lattice of positive metal ions surrounded by delocalised electrons that can move freely throughout the structure.

How is a metallic bond formed?

Metal atoms lose their outer-shell electrons to become positive ions; the electrons become delocalised, and electrostatic attraction between ions and electrons forms metallic bonds.

List the three main factors that affect the strength of metallic bonding.

1) Number of delocalised electrons per atom (more → stronger) 2) Charge of the metal ion (higher charge → stronger) 3) Size of the metal ion (smaller radius → stronger).

Explain why metals have high melting and boiling points.

Strong electrostatic forces between positive ions and delocalised electrons require large amounts of energy to break.

Why are metals good electrical conductors?

The delocalised electrons are free to move throughout the lattice and carry electric current.

Why are metals malleable and ductile while ionic compounds are brittle?

Metal ion layers can slide past each other while delocalised electrons maintain attraction; in ionic lattices, shifting layers brings like charges together, causing repulsion and fracture.

Compare metallic, ionic, and covalent bonding in terms of particles and electron movement.

Metallic: metal ions + delocalised electrons, electrons free to move. Ionic: oppositely charged ions, electrons transferred. Covalent: non-metals share electrons in orbitals.

Why do different metals have different melting points?

Metals with more delocalised electrons, higher ionic charge, and smaller ion size have stronger metallic bonds, producing higher melting points (e.g., Mg²⁺ > Na⁺).

How does metallic bonding account for a metal's high density and lustre?

High density: closely packed ions in a regular lattice. Lustre: delocalised electrons reflect light from the metal's surface.