The thermal stability increases down the group.

BeCO$_3$ is more thermally stable than MgCO$_3$ due to the high polarizing power of Be$^{2+}$

BaCO$_3$ decomposes at a much higher temperature than MgCO$_3$.

The decomposition of these carbonates yields the corresponding metal oxide and CO$_2$.

${\rm{Ca}}$

${\rm{Mg}}$

${\rm{Zn}}$

${\rm{Fe}}$

${\rm{Ba}}{\left( {{\rm{OH}}} \right)_2}$

${\rm{Ca}}{\left( {{\rm{OH}}} \right)_2}$

${\rm{Be}}{\left( {{\rm{OH}}} \right)_2}$

${\rm{Mg}}{\left( {{\rm{OH}}} \right)_2}$

Portland cement

Sorel’s cement

Double salt

None of these

Metal – Li, Characteristic colour to an oxidizing flame-Crimson red

Metal – Na, Characteristic colour to an oxidizing flame-Yellow

Metal – K, Characteristic colour to an oxidizing flame-Violet

Metal – Cs, Characteristic colour to an oxidizing flame-Green

Magnesium

Calcium

Strontium

Radium

Ca

Mg

Both Ca and Mg

Neither Ca nor Mg

${\rm{KCl}}$

${\rm{N}}{{\rm{H}}_4}{\rm{Cl}}$

${\rm{C}}{{\rm{a}}_3}{\left( {{\rm{P}}{{\rm{O}}_4}} \right)_2}$

${\rm{NaHC}}{{\rm{O}}_3}$

Amphoteric

Strongly acidic

Strongly basic

Neutral

Calcium

Aluminium

Sulphur

Iron

${\rm{KCl}}$

${\rm{N}}{{\rm{H}}_4}{\rm{Cl}}$

${\rm{C}}{{\rm{a}}_3}{\left( {{\rm{P}}{{\rm{O}}_4}} \right)_2}$

${\rm{NaHC}}{{\rm{O}}_3}$