Physical properties of metals:

Good conductors of heat and electricity. In metals, the positive ions are surrounded by a sea of electrons and these are responsible for their conductivity.

High melting point and boiling point

They are malleable and ductile ,so they can be bent and stretched without breaking.

In most of the metals the atoms are highly close packed so they have high density.

They have a shiny appearance

Metals exist in solid state at room temperature except for mercury,which is in a liquid state at room temperature.

Chemical properties of metals:

A more reactive metal readily reacts with other elements. The most reactive metals will react even with acid. Example :If we put a small piece of sodium metal in water,sodium reacts exothermally with water producing hydrogen and metal hydroxide..

2Na(s) + 2H₂O(l) → 2NaOH(aq) +H₂(g)

Metal reacts with oxygen in the air to form oxides. Examples:

4Na +O₂ → 2Na₂O

4Al +3O₂ → 2Al₂O₃

Some metals react with acid and replace hydrogen with acid.

Zn +H₂SO₄ → ZnSO₄ + H₂

Single displacement reactions:Asingle displacement is an important type of chemical reaction.It is also called substitution reaction. In these reactions, a free element displaces another element from its compound, producing a new compound.The reaction is usually written as

A +BC →AC +B

Single displacement reactions are all oxidation-reduction reactions. For example

Oxidation: Al (0 → +3)

0 +3 -2 +3 -2 0

2Al + Fe2O3 → Al2O3 + Fe

Reduction: Fe( +3 → 0)

Definition of Displacement reaction: The chemical reaction by which one element takes the position or place of another element in a compound.

Displacement reactions are very common in metals.They can be used to find out the relative reactivities of metals .In a displacement reaction, a more reactive metal can displace a less reactive metal from its salt solution. The reaction is often known as metal displacement reaction.

Over the years, enterprising scientists have thought of many ways to categorize and arrange the known metallic elements - the Periodic Table of the Elements being the best known - but perhaps the most accessible and useful is the Reactivity Series (shown below). The following series includes the best- known metals

Some of the commonly used metals have been arranged in the decreasing order of reactivity. This is known as reactivity series or activity series..The activity series of metals is an important concept in chemistry. The activity series(figure above) of metals is an important tool for predicting the products of displacement reaction and the reactivity of metals in other reactions. Potassium is the most reactive metal, while platinum is the least reactive. The same reactivity can be shown by a table (shown below) showing reaction of metals with water, acid and oxygen.

Collage shows the reactivity trend of metals, as depicted in figure above. Gold and silver are very unreactive while potassium and sodium are very reactive.

A metal can replace metals listed below it in the activity series, but not above. For example, sodium is highly active and thus able to replace hydrogen from water.

2Na(s) +2H₂O → 2NaOH(aq) +H₂(g)

The reactivity series determines qualitatively characteristics such as the reactions with water, oxygen and acids as demonstrated above. However it is defined by the nature of the metals in single displacement reactions

When a metal in elemental form is placed in a solution of a metal salt it may be , overall more energetically feasible for this elemental metal to exist as an ion and ionic metal to exist as the element. Therefore the elemental metal will displace the ionic metal over time, thus the two swap places. Only a metal higher in the reactivity series will displace another. Figure below shows metal magnesium reacts with copper sulphate solution, they change into colourless magnesium sulphate and metal copper

Aluminium can displace Cu from copper sulphate solution(shown in above figure), Zn from zinc sulphate solution, and Fe from ferrous sulphate solution.

2Al + 3ZnSO₄ → 3Zn +Al₂(SO4)₃

2Al + 3CuSO₄ → 3Cu +Al₂(SO4)₃

2Al + 3FeSO₄ → 3Fe +Al₂(SO4)₃

If small pieces of copper are added into solutions of zinc sulphate, aluminium sulphate and ferrous suphate, no reactions take place. So, copper is less reactive than zinc, aluminium and iron

When an iron nail is dipped in the solution of copper sulphate solution , after a while the solution changes into the colour of green becoming iron sulphate and a brown substance is found on the iron nail which is copper so we get to know that the displacement reaction is produced .iron is higher than Cu in activity series ,therefore iron displaces Cu, in copper sulfate becoming iron sulfate and browm Cu get deposited on iron

when Cu is dipped in ferric sulfate — no reaction occurs(shown in figure below)

Fe (s) + CuSO4 (aq) → Fe SO4 (aq) + Cu (s)

Cu (s) + FeSO4 (aq) → No Reaction

Reactivity series of metals : We know that some metals are more reactive than the others.. Classification of Elements we have seen that the reactivity of elements decreases as we go from left to right in periodic table.

In the alkali group, as we go down the group we have elements Lithium(Li),Sodium(Na), Potassium(K), Rubidium(Rb), Cesium(Cs) and Francium(Fr).They all only one electron in their outermost shells. All these elements show metallic properties and have valency +1.. They give up electrons easily. Reactivity or the ease with which these elements give off their electrons increases with size of the atoms. The size of the atom increases from Li to Fr.. The outermost electron is less loosely bound in Fr than in Li as in Fr the distance between the last electron and the positive nucleus is large. this makes the force of attraction binding or holding the electrons to be less in magnitude. Thus K will give up electrons more easily than Na.;

As we go down the alkaline earth group we have elements Beryllium(Be), Magnesium(Mg), Calcium(Ca), Strontium(Sr), Barium(Ba), Radium(Ra).They have two electrons in their outer most shell and their valency is +2 as they give up two electrons to form compounds. The elements in group II A are not as metallic as the alkali metals.. Reactivity or the ease with which these elements give off their electrons increases with size of atoms .The size of atoms increases from Be to Ra.. The outermost electron is loosely bound in Ra than in Be, as in Ra the distance between the last electron and the positive nucleus is large. this makes the attractive force binding or holding the electron to be less in magnitude. Thus Ca will give up electron more easily than Mg. This makes Ca more reactive than Mg.;

The transition group element such as Zn, Fe, Sn ,Pb ,Cu are also metallic and reactive. But the ease with which they loose electrons is less than that we see in alkali or alkaline earth

Na ,K ,Li,alkali metals from group 1 A.Ca,Mg are alkaline earth metals from group 2A are reactive but are less reactive than alkali metals. The transition group elements such as Zn, Fe, Sn. Pb. Cu are also metallic and reactive. But the ease with which they loose electrons is less than that we see in alkali or alkaline earth metals

The table above shows the reactivity series of metals. Hydrogen has been included in the table, although it is a non-metal. H is a special case because although it is a non-metal, it gives off an electron while forming bonds.

Metals which are more reactive than hydrogen are K, Na, Ca, Mg, Al, Zn, Fe, Sn and Pb. These metals can displace H from water or dilute acids and liberate hydrogen gas.

Metals which are less reactive than hydrogen are Cu, Hg, Ag. These metals do not replace H in a reaction with water or dilute acids.

If you hang a coil of copper wire in some colourless silver nitrate solution, the copper gets covered in silver - partly as a grey fur, and partly as delicate crystals. The solution turns blue.cu is higher than Ag therefore silver nitrate becomes Cu nitrate ,Cu gets covered with silver

From the reactivity series of metals shown in the above table we can say that :

Metals that are more reactive than H are placed above H

Metals whose reactivity is less than that of H are placed below H

For example elements like Copper, Gold and Silver are found as pure elements in nature whereas things like Sodium, Lithium and Potassium are never found as a pure element. This is simply because an element like Silver is much lower on the metal activity series and therefore it cannot displace many other elements unless it is placed inside a solution with gold ions which rarely occurs in nature.

On the other hand a metal like Potassium is very high on the metal activity series therefore it is very reactive. This characteristic that it possesses makes it impossible to find as a pure substance because it will very easily react with water which is in abundance in nature.

The reactivity series gives an idea as to which element is capable of displacing other elements in a displacement reaction

Using activity series it is simple to determine if certain metals will react with other metals. For example ,if Copper was mixed with Calcium sulphate solution there would be no reaction because the copperis lower than Calcium .Similarly if lead was mixed with Zinc sulphate then there would be no reaction.

Learning Outcomes of collage

1. 1. Students understand the terms like metals, metal displacement reaction, reactivity series etc.

2. 2. Students acquire skills to perform and visualize the reactions of Al, Zn,Fe and Cuwith the following salt solutions

Aluminium sulphate

Zinc sulphate

Ferrous suphate

Copper sulphate

3. Students can analyse the meaning of reactivity series of metals based on the inferences from the experiment..

Collage showing metal reactivity gives the message that proper utilization of this knowledge is in hands of mankind and if used properly the beautiful earth environment can be saved: A heritage given to us by our forefathers which we have to handover to coming generations very safely.

References

https://www.google.co.in/search?q=metal+reactivity+series+experiment

http://amrita.olabs.co.in/?sub=73&brch=3&sim=59&cnt=1

http://wiki.answers.com/Q/Iron_nail_dipped_in_copper_sulphate_solution#ixzz1YTIgo2ND

http://scienceray.com/chemistry/metal-activity-series/#ixzz1Y6B4aIPT