2.3A Metallic Bonding

What are the characteristics of metals?

• Small number of valence electrons

• Low ionization energy, are prone to losing electrons

• High melting and boiling points

Why do Metallic Bonds occur? What happens as a result?

Metals in their elemental state have no other element to accept their electrons and form an ionic compound.

Their electrons are held loosely by the metal’s nucleus and tend to “wander off”, becoming delocalized.

Metal atoms losing valence electrons become positive ions. The delocalized electrons are free to travel throughout the positive ion lattice, and are not associated with one particular metal nucleus.

What are Metallic Bonds?

the electrostatic attraction between a lattice of cations and delocalized electrons. It is an array of positive ions in a sea of electrons. “Electron Sea Theory”

What does the strength of a metallic bond depend on?

1. the charge of the ions

2. the radius of the metal ion

What are the Metallic Properties mentioned in class?

1. Good Electrical Conductivity

2. Good Thermal Conductivity

3. Malleable, can be shaped under pressure; Ductile, can be drawn into threads

4. High Melting Point

5. Shiny Lustrous Appearance

Why do Metals have Good Electrical Conductivity?

Many mobile delocalized electrons are present. They can move through the metal structure in response to an applied voltage.

Why do Metals have Good Thermal Conductivity?

Delocalized electrons and closely packed ions allow for efficient energy transfer.

Why are metals malleable/ductile?

Movement of delocalized electrons is non-directional and random throughout the cation lattice. The metallic bond remains intact while conformation changes under applied pressure.

Why do Metals have High Melting Points?

Large amounts of energy are required to break strong metallic bonds and separate atoms.

Why are metals lustrous (shiny)?

Delocalized electrons in metal crystal structure reflect light