Alkali Metals

 

The group I comprising Li, Na, K, Rb, Cs & Fr are commonly called alkali metals. Francium is radioactive and has a very short life (half life of 21 minutes), therefore very little is known about it.

 
Electronic Configuration
 

The general electronic configuration of alkali metals may be represented by [noble gas]  where n = 2 to 7

 
 
 
Table – I

[Some Physical properties of group 1 elements (alkali metals)]

 
Property
 
Elements
Li
Na
K
Rb
Cs
Fr
(Radioactive)
Atomic Number
3
11
19
37
55
87
Electronic Configuration
2s’
3s’
4s’
5s’
6s’
7s’
Atomic Mass
6.94
22.99
39.10
85.47
13.91
223
Metallic radius (pm)
152
186
227
248
265
375
Ionic radius (M+/pm)
76
102
138
152
167
180
Ionization enthalpy
(kJ mol–1)
I
520
496
419
403
376
II
7298
3562
3051
2633
2230
Electro negativity
(Pauling Scale)
0.98
0.93
0.82
0.82
0.79
 
Density/g cm–3 (at 298K)
0.53
0.97
0.86
1.53
1.90
 
Melting point/K
454
371
336
312
302
 
Boiling point/K
1615
1156
1032
961
944
 

E°(V) at 298K for

M+(aq) + e→ M(s)

–3.04
–2.714
–2.925
–2.930
–2.927
 

Occurrence in

Atmosphere
18*
227**
1.84**
78.12*
2.6*
 
 
*ppm (parts per million)               ** percentage by weight

Alt text: physical properties of Alkali metals

 
 
 
Illustration:

          Why Group 1 elements are called alkali metals?

Solution:

        The Group 1 elements are called alkali metals because they form water soluble hydroxides.

 
Exercise:

        Write three general characteristics of the elements of s-block of the periodic table which distinguish them from the elements of the other blocks.

 
Exercise:
        Which alkali metal is most abundant in earth’s crust?
 
Name
Email Id
Mobile

Exam
Target Year

Related Resources
Difference-Alkaline Earth Metals and Alkali Metals

Difference between alkaline earth metals and...

Properties of Lithium

Properties of Lithium (a) Physical Properties (i)...

Oxides of Magnesium and Calcium

Oxides of Magnesium and Calcium Oxides of Mg, Ca...

Anomolous Behaviour of Lithium

Anomolous Behaviour of Lithium and its Diagonal...

Halides of Alkali Metals

Halides of Alkali metals:- The alkali metals...

Alkaline Earth Metals

Alkaline Earth Metals The group 2 of the periodic...

Chemical Properties of Group II Elements

Chemical Properties of Group – II elements...

Magnesium Sulphate

Magnesium Sulphate Magnesium sulphate, Epsom salt...

Physical Properties of Alkali Metals

PHYSICAL PROPERTIES (i) All the alkali elements...

Properties of Sodium

Properties of Lithium (a) Physical Properties (i)...

Carbonates and Bicarbonates of Magnesium and Calcium

Calcium Carbonate (CaCO 3 ) It occurs in nature as...

Solved Examples on Alkali Metals

Illustration: What is the most reactive alkali...

Salts of Oxoacids

Salts of oxoacids Since the alkali metals are...

Anamolous Behaviour of Beryllium

Anamolous Behaviour of Beryllium The properties of...

Plaster of Paris

Plaster of paris, CaSO 4 .1/2 H 2 O or (CaSO 4 ) 2...

Occurrence and uses of Alkaline Earth Metals

Occurrence and uses of alkaline earth metals...

Compounds of Alkaline Earth Metals

Halides The alkaline earth metals combine directly...

Magnesium

Magnesium Metal Magnesium occurs as magnesite MgCO...

Physical Properties of Alkaline Earth Metals

Physical Properties of Alkaline Earth Metals...

Chemical Properties of Alkaline Earth Metals

Reaction with hydrogen – (Formation of...

Minerals of Lithium

Minerals of Lithium Difficulties encountered...

Introduction of S and P Block Elements

INTRODUCTION The elements in the long form of the...

General Characteristic of Compounds of Alkali Metals

General characteristic of the compounds of the...

Some other Compounds of Alkali Metals

Bicarbonates of Metals (Na, K) Sodium Bicarbonate...

Properties of Magnesium

Properties of Magnesium Physical Properties (i)...

Sodium

Sodium Sodium is the 7 th most abundant element by...

Physical Characteristics of Alkaline Earth Metals

Melting and boiling points The alkaline earth...

Hydroxides of Alkali Metals

Hydroxides of Metals (Na, K) Sodium Hydroxide...

Carbonates of Alkali Metals

Carbonates of Metals (Na, K) Sodium Carbonate...

Chemical Properties of Alkali Metals

CHEMICAL PROPERTIES The alkali metals are highly...

Oxides of Alkali Metals

Oxides of Alkali Metal Oxides of Sodium: The...

Characteristics of Alkaline Earth Metal Compounds

General characteristics of compounds of the...

Hydroxides of Magnesium and Calcium

Hydroxides of Mg & Ca Magnesium Hydroxide...