The molecular weight of resin is \\\\(206\\\\) g/mol.\\\\(1\\\\) g of resin corresponds to \\\\(\\dfrac {1}{206}\\\\) moles. \\\\(1\\\\) mole of calcium ions will displace \\\\(2\\\\) moles of sodium ions from resin.\\\\(1\\\\) mole of resin contains \\\\(1\\\\) mole of sodium ions and can uptake upto \\\\(0.5\\\\) moles of calcium ions.Hence, \\\\(1\\\\) g of resin will uptake \\\\(\\dfrac {1}{206} \ imes 0.5 =\\dfrac{1}{412}\\\\) moles of calcium ions.