s block elements chapter summary in 2 Minutes

S - block elements chapter summary in 2 Minutes.....

Physical Properties of Alkali Metals:


These are soft in nature and can be cut with the help of knife except the lithium.  


The atoms of alkali metals have the largest size in their respective periods. 


The first ionization energy of the alkali metals are the lowest as compared to the elements in the other group. 


The alkali metals show +1 oxidation state. 


The alkali metals have low values of reduction potential (as shown in table-I) and therefore have a strong tendency to lose electrons and act as good reducing agents. 


The melting and boiling points of alkali metals are very low because the intermetallic bonds in them are quite weak. 



ll the alkali metals form ionic (electrovalent) compounds. 


The alkali metals are good conductors of heat and electricity. 


Alkali metals (except Li) exhibit photoelectric effect 


The alkali metals and their salts impart a characteristic colour to flame.




Hydroxides of Alkali Metals:

a)All the alkali metals, their oxides, peroxides and superoxides readily dissolve in water to produce corresponding hydroxides which are strong alkalies.


2Na + 2H2O → 2NaOH + H2                   


Na2O + 2H2O 2NaOH               


Na2O2 + 2H2O → 2NaOH + H2O2               


2KO2 + 2H2O → 2KOH + H2O2 + O2 




Halides of Alkali metals:

M2O + 2HX → 2MX + H2O                

MOH + HX → MX + H2O               

M2CO3 + 2HX → 2MX + CO2 + H2O (M = Li, Na, K, Rb or Cs)

(X = F, Cl, Br or I)..