The reactivity series of metals.

What is it?

The reactivity series is a way of classifying metals.  Most metals have similar physical properties but may differ in other ways; this is where their reactivity comes in.  If we know the reactivity of a certain metal we can predict their positioning in the periodic table.  With over seventy metallic elements in the periodic table a method of arranging them is needed, so they are arranged by how reactive they are, with the more reactive metals at the bottom of the periodic table and the least reactive nearer the top.

These are the top ten reactive metals in the periodic table: -

1.      Potassium-K

2.      Sodium-Na

3.      Lithium-Li

4.      Calcium-Ca

5.      Magnesium-Mg

6.      Aluminium-Al

7.      Zinc-Zn

8.      Iron-Fe

9.      Lead-Pb

10.  Copper-Cu

How well do these metals react with water?

Copper, iron, lead, aluminium, magnesium, and zinc do not react with water at all.  When the metal was placed in the water it just sank to the bottom of the container and no reaction took place.

Calcium however did react with cold water. The metal sank, but turned the water cloudy. The metal then began to bubble and produced hydrogen. It produced an alkaline solution.

Lithium did react with cold water. This time the metal floated in the water. Again the metal bubbled and produced hydrogen. It also produced an alkaline solution.

Sodium floated in the cold water and reacted. The sodium reacted into a silvery ball, and burned on the surface to produce hydrogen. It produced an alkaline solution.

Potassium is the most reactive metal. It caught fire, floated, and exploded on the water burning a lilac flame. It turned the water into an alkaline solution

EXAMPLE:

Sodium  +  water   =   sodium hydroxide +  hydrogen

                                                              2Na    +     2H2O                 =        2NaOH             +                   H2

Do the remaining metals react with steam?

Magnesium is the only remaining metal, which will react with steam. When magnesium ribbon is placed in a test tube along with mineral wool, which is soaked in water and heated very strongly, to produce steam, the magnesium ribbon will burn giving off a white glow and giving off hydrogen.

Magnesium + water (steam) = magnesium oxide + hydrogen.

                                                                             Mg         +     H2O              =        MgO           +      H2

The magnesium oxide, which is in powder form, is slightly alkaline.

Iron, aluminium, zinc, copper and lead still will not react.

Will the rest react with dilute hydrochloric acid?

Aluminium, zinc and iron all react with dilute hydrochloric acid to form metal chlorides by displacing hydrogen. Tin and lead however also react with dilute hydrochloric acid but the reaction is very slow.

EXAMPLE:

Zinc   +   Hydrochloric acid   =   Zinc chloride  +  Hydrogen

                Zn                                      2HCl                                                   =                       ZnCl2                 +          H2

Copper does not react at all with dilute hydrochloric acid.

NB It would be extremely dangerous to add potassium, sodium or lithium to dilute hydrochloride acid as they react dangerously fast and could cause an explosion. 

Displacement reactions.

In displacement reactions a more reactive metal will displace a less reactive metal.

EXAMPLE:

Magnesium will displace zinc from a solution of zinc sulphate.

Sorry, the formatting lost the sad and happy faces.

Mg should start sad and finish happy.

Zinc should go the opposite way.

magnesium

Zinc sulphate

Magnesium sulphate

zinc

 

By Nicola O' Kane: Y11 Loreto College, Coleraine.