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 Chemistry Section C : A Closer Look at Metals

Part 2: Information

A. Physical Properties

Metals are elements that are found on the left hand side of the periodic table (see Section B). We have already seen from Section A that metals have the following properties.

  • They are shiny solids (except mercury)
  • Generally high melting and boiling points.
  • Strong in compression and tension.
  • Malleable.
  • Ductile.
  • Good conductors of heat and electricity.

Internet site link
Go to GCSE module 5 and then N-m05-12 Metals and non-metals. You can print out a sheet with the properties of metals compared to non-metals

B. The Structure of Metals

The properties of metals can be explained by looking at the way their atoms are arranged. The structure of metals

Metals are crystalline solids, their atoms are packed tightly together in a regular pattern. There are three main types of arrangement on the metal.

1.Body Centred Cubic (BCC)

An atom at each vertex and one in the centre of the cube.
2.Face Centred Cubic (FCC)

An atom at each vertex and in the centre of each face.
3.Hexagonal Close Packing (HCP)

 

B. The Structure of Metals continued

The way the atoms are arranged can be used to explain several of the physical properties of metals.

1. Conduction of electricity

Go to Internet site link
Then click on Chemistry
Then click on Bonding

If you look at the diagram you should be able to see that there is a 'mobile sea' of electrons, which hence allow the metals to conduct electricity.

2. The strength of metals and other physical properties can be explained by looking at the way the atoms are tightly packed together.

C. Chemical Properties

Link to experiment

1.With Oxygen

Metals that react with oxygen do so to form substances called oxides. The process is called oxidation.

METAL + OXYGEN

METAL OXIDE
example      

COPPER + OXYGEN

COPPER OXIDE

2Cu    +    O2

2CuO

Extra Information :

During the oxidation process the metal loses electrons and the oxygen gains electrons.
We can represent the reaction as follows:

2Cu    +    O2

2Cu2+O2-
This is a combination of    

Cu    -    2e

Cu2+
and    

O2    +    4e

2O2-

These are known as half equations.

2.With dilute Acids
(See also Part D acids + alkalis)


Example: Hydrochloric acid or sulphuric acid.

Metals that react with dilute acids do so to produce hydrogen gas and a metal chloride with hydrochloric acid or a metal sulphate with sulphuric acid.

*We can test for hydrogen gas by holding a lighted splint to the mouth of the test tube and there will be a 'pop`.

Example:

Zn  +  2HCl

ZnCl2    +  H2

Extra Information :

During the reaction the metal loses electrons and the hydrogen ion present in the acid gains electrons.

Zn   +    2e

Zn2+

2H+  +    2e

H2
The Cl- remains unchanged and is known as a spectator ion
The overall ionic equation is:

Zn   +    2H+

Zn2+ + H2

3.With dilute Alkalis
(See also Part D acids + alkalis)

Some metals like zinc and aluminium react with dilute alkalis such as sodium hydroxide to produce hydrogen.

4.With water

Metals that react with cold water do so to form a Metal hydroxide + Hydrogen.
Examples: sodium, potassium, calcium and magnesium (slowly)

Metals that react with steam do so to form a metal oxide and hydrogen.
Examples as above + zinc and iron.

Several metals do not react at all. Examples: Copper, silver and Gold.

Continued
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