Reactions Between Metals and Non-metals

 

1. Elements can be classified into two main groups, namely metals and non-metals.

 

2. Metals are extracted from the mineral ores found within the Earth's crust.

 

3. Properties of metals are:

    (a) Good conductors of heat and electricity

    (b) Malleable (can be hammered into various shapes)

    (c) Ductile (can br drawn into wires)

    (d) High melting and boiling points

    (e) Can be polished to get a shiny surface

    (f) High density

    (g) Solid at room temperature (except mercury, which is liquid)

 

4. Examples of metals are potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, gold, silver and mercury.

   

5. Properties of non-metals are:

    (a) Poor heat conductor

    (b) Do not conduct electricity (except carbon)

    (c) Brittle (easily fractured when hammered)

    (d) They are neither malleable nor ductile

    (e) Low melting and boiling points

    (f) Dull appearance (cannot be polished to get a shiny surface)

    (g) Low density

    (h) Exist either as gases, liquids or solids at room temperature

 

6. Carbon and sulphur are non-metals in solid forms; bromine is an example on non-metal in liquid form. Oxygen, hydrogen, nitrogen, helium and chlorine are examples of non-metals in gaseous form.

 

7. Most metals react with non-metals to form compounds.

 

Reaction Between Metals And Non-Metals

1. When metals react with oxygen, metal oxides are formed.

 

2. The general equation in words for the reaction between a metal and oxygen is given below.

                    \(Metal\quad +\quad oxygen\quad \rightarrow \quad metal\quad oxide\)

 

3. Below shows some examples.

                       \(Iron\quad +\quad oxygen\quad \rightarrow \quad iron\quad oxide\)

        \(Aluminium\quad +\quad oxygen\quad \rightarrow \quad aluminium\quad oxide\)

 

4. Similarly, when metals react with sulphur, metal sulphides are formed.

 

5. The general equation in words for the reaction between a metal and sulphur is given below.

                  \(Metal\quad +\quad sulphur\quad \rightarrow \quad metal\quad sulphide\)  

 

6. Below are some examples.

     \(Magnesium\quad +\quad sulphur\quad \rightarrow \quad magnesium\quad sulphide\) 

               \(Copper\quad +\quad sulphur\quad \rightarrow \quad copper\quad sulphide\)

 

7. Metals react with oxygen and sulphur at different rates. The more reactive metals will react more readily compared with the less reactive ones.

 

8. The very reactive metals react with oxygen and sulphur vigorously. Sodium and potassium are examples of metals which react vigorously with oxygen. They have to be stored under an oil surface in a stoppered bottle to prevent air from reaching and reacting with them.

 

9. Magnesium, zinc, aluminium and iron are reactive metals which react easily. Copper and lead are less reactive metals which react slowly, whereas gold and silver are very unreactive metals that do not react with oxygen and sulphur.