2.3A Metallic Bonding

im scared for the chem test

What are the Characteristics of Metals?

• small # of valence electrons

• Low ionization energy,

  • prone to losing electrons

• High melting and boiling points

Tell me about Metallic Bonding. Why does it occur?

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.

So what exactly is a Metallic Bond?

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 determines a metallic bond’s strength?

1. the charge of the ions

   1. same as # of electrons lost

2. the radius of the metal ion

Metallic bond strength _________ down a group because….

decreases

the ionic radius increases

Why are metals good conductors of electricity?

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

Why are metals good conductors of heat?

due to the delocalized electrons and closely packed ions allow for efficient energy transfer

Why are metals malleable (ability to be shaped under pressure) and ductile (can be drawn into threads)?

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