Most reactive metals in the periodic table

Introduction :
A periodic table is an arrangement of all the known elements in vertical groups and horizontal rows so that the elements with similar physical and chemical properties are placed in the same group.In 1912, Moseley proposed the modern periodic law.  The modern periodic law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.  There are 18 vertical columns and 7 horizontal rows.The Vertical columns present in the periodic table are represented by Groups.  The horizontal rows present in the periodic table are represented by Periods.

The most reactive metals in the periodic table are:

• Lithium( Li)
• Sodium (Na)
• Potassium(K)
• Rubidium(Rb)
• Caesium(Cs)
•  Francium(Fr)

These elements are called Alkali Metals Periodic Table because their oxides and hydroxides dissolve in water to produce strong alkalies.  They are most reactive and highly electropositive elements in the periodic table.  Group first elements of the periodic table are called as alkali metals.  These are very reactive metals we cannot get freely in nature.  There is only one electron in the outer most shell of these metals.  During the formation of ionic bonding with the other elements, these elements ready to lose one electron. 

In comparison to all metals, alkali metals are more ductile, malleable and good conductors of heat and electricity.  The most reactive elements in this group are Cesium and francium.  If alkali metals are exposed to water they can explode.

Colour of alkali metals during flame test:

Metal ion	Flame colour
Lithium	Crimson red
Sodium	Golden yellow
Potassium	Lilac (pale violet)
Rubidium and caesium	Violet

Properties of Most reactive metals in the periodic table (alkali metals):

1. Alkali metals are the light metals.  Their density is low because of larger atomic volumes.
2. Alkali metals have low ionization energies because the last electron is present in the outermost s-orbital and the removal of electron is easy.
3. Due to low ionization energy , alkali metals are highly electropositive.
4. The metallic character of alkali metals increases from lithium to caesium due to low ionization energy.
5. Alkali metals are powerful reducing agents because they have very low reduction potentials.
6. Alkali metals are exposed to air, they tarnish rapidly due to the formation of oxides on the surface.  Hence they are most reactive metals kept under kerosene or paraffin oil and protected from the action of air.