2.7 Metallic Bonding

Giant Metallic Lattices 🔑

Metal atoms possess relatively few electrons in their outer shells. When metal atoms pack together to form a solid structure, a unique bonding arrangement develops:

Formation of Metallic Structure:

When metal atoms are packed closely together, each metal atom loses its outer electrons into a shared pool or 'sea' of delocalised electrons. These electrons are no longer associated with any particular atom—they are free to move throughout the entire structure.

Formation of Positive Ions:

Once a metal atom loses electrons, it is no longer electrically neutral. The atom becomes a positive ion because:

• It has lost negatively charged electrons
• The number of protons in the nucleus remains unchanged
• This creates a net positive charge

Resulting Structure:

The structure of a metal consists of:

• Positive metal ions arranged in a regular, repeating pattern (giant lattice)
• Delocalised electrons that can move freely between the ions
• These mobile electrons form a kind of electrostatic 'glue' holding the entire structure together

What is Metallic Bonding? ⚡

Metallic bonding is defined as:

This bonding can be visualized as a three-dimensional lattice structure where:

• Large positive metal ions are arranged in regular layers
• Smaller mobile electrons move freely throughout the spaces between these ions
• The electrostatic attraction between the positive ions and negative electrons holds the structure together

Key Features:

• The electrons are delocalised (not restricted to orbiting one positive ion)
• The bonding acts in all directions throughout the structure
• The attractive forces are strong and extensive