Number of moles of calcium ions present in 1 mole of  Calcium carbonate are ( ${\mathrm{N}}_{\mathrm{A} }=\mathrm{Avagadro}\text{'}\mathrm{s} \mathrm{number}$)

Atomicity of CaCO₃ is 5 ;

One molecule of CaCO₃ contains…1 atom of ‘Ca’….1 atom of ‘C’…3 atoms of ‘O’…5 atoms ;

One mole of CaCO₃ contains…1 gram atom or 1 mole of ‘Ca’(N_A)….1 gram atom or 1 mole,of ‘C’(N_A)…3 gram atoms or 3 mole atoms of ‘O' (3N_A)

One mole of CaCO₃ contains….5 gram atoms (5N_A) ;

One mole of CaCO₃ contains…N_A molecules ;

One mole of CaCO₃ contains….2 moles(2N_A) of ions…One mole(N_A) of Ca²⁺…One mole(N_A) of ${\mathrm{CO}}_3^{2-}$

 ${\mathrm{CaCO}}_3\rightleftharpoons {\mathrm{Ca}}^{2+}+{\mathrm{CO}}_3^{2-} ;$