\(S{c^{3 + }}\, \to \,\,3{d^0}\)
\(M{n^{2 + }}\, \to \,\,3{d^5}4{s^0}\);
\(Z{n^{2 + }}\, \to \,\,3{d^{10}}4{s^0}\)
In \(M{n^{2 + }}\) number of unpaired \( d\) \({e^ - } = 5\).
So it has maximum magnetic moment according to the formula. \(\mu = \sqrt {n(n + 2)} \)
$(1)\,Cu^{2+}$ $(2)\,Ti^{4+}$ $(3)\, Co^{2+}$ $(4)\,Fe^{4+}$