Lesson 4: Metallic Bonds and Properties of Metals

physical property

a characteristic of matter that can be observed or measured without altering the sample’s composition 

Eg: 

• Conductivity  

• High Metling nad Boiling Points 

 

metallic bond

 the electrostatic attraction between the metallic cation and the delocalized electrons. 

The electron sea model proposes that all metal atoms in a metallic solid contribute their valence electrons to

form a “sea” of delocalized electrons that surrounds the metal cations in a metallic lattice. 

The physical properties of metals at the bulk scale can be explained by

metallic bonding.

These properties provide evidence of the strength of metallic bonds. 

 

Examples of physical properties of metals: 

 

• Melting and boiling points 

• Thermal and electrical  conductivity 

• Malleability, ductility, and durability 

• Hardness and strength 

• In general, metals have moderately high melting points and high boiling points. 

During melting, metal ions can slide past each other without breaking the entire metallic bonding network, but during boiling atoms must 

 

completely separate from the metallic lattice 

 

metals are good conductors because

The movement of mobile electrons around positive metallic cations

 

Mobile electrons move heat from

one place to another quickly.  

Mobile electrons easily move as

part of an electric current when an electric potential is applied to a metal. 

Metals are malleable 

can be hammered into sheets

Metals are ductile 

can be drawn into wire

Once force is applied it causes metal ions to

move through delocalized electrons, making metals malleable and ductile. 

When struck, one plane of atoms slide past another without

 breaking bonds.  -not brittle but ductile and malleable

Metals are shiny – Metallic Luster: 

• What happens to the electrons when they absorb energy? 

• They jump to a higher energy level (to an excited state) 

• And return back to a lower energy level  

(in the process of going back they EMIT ENERGY as visible light) 

 

The delocalized/mobile electrons in the metallic lattice readily absorb

photons of light (energy) and jump to higher (excited) energy level.

When the electrons return to lower energy level they emit 

(release) energy in the form of light; GIVING METALS THEIR SHINE   

The delocalized electrons absorb light energy, move to excited state, and re-emit light when returning to lower energy level. This

gives metals their metallic luster 

Metallic Bond Strength increases:  

• With the increase in number of delocalized electrons 

• Charge of metal cation 

• • Small size of metal atom/ion 

An alloy is a

mixture of elements that has metallic properties.  

Examples of allys

 stainless steel, brass, cast iron 

The properties of alloys generally differ from the

properties of the elements that they contain.  

Example: Steel is iron mixed with at least one other element.  

Some properties of iron are present, but steel is stronger than iron.