QUE : EXPLAIN THE STABILITY OF METAL CARBONATES OF GROUP 1 (ALKALI) AND GROUP 2 (ALKALINES EARTH METALS) '

ANS :Stability of carbonates of group 1 and group 2 increases down the group  .
              Li₂CO₃< Na₂CO₃< k₂CO₃ < Rb₂CO₃ <  Cs₂CO₃ 
Reason 1- By ionisation enthalpy (I.E)
As I.E. increases down the group , breaking of  M - CO₃²-  bond becomes difficult and becomes more stable.
 Reason 2- By HSAB PRINCIPLE ( HARD SOFT ACID BASE THEORY )
             CO₃²-   Anion is a big anion so better stabilized by big  cation.

GROUP 1 METAL CARBONATES

 GROUP 2     Stability order

                         BeCO₃< MgCO₃< CaCO₃ < SrCO₃ <  BaCO₃
 

GROUP 2 METAL CARBONATES