\(\lambda = \frac{h}{{mv}}...(i)\)
\(K.E. = \frac{1}{2}m{v^2}\)
\({v^2} = \frac{{2KE}}{m}\)
\(v = \sqrt {\frac{{2KE}}{m}} \)
Substituting this in equation \((i)\)
\(\lambda = \frac{h}{m}\sqrt {\frac{m}{{2KE}}} \)
\(\lambda = h\sqrt {\frac{1}{{2m(K.E.)}}} ...(i)\)
i.e. \(\lambda \propto \frac{1}{{\sqrt {KE} }}\)
\(\therefore \) when \(KE\) become \(4\) times wavelength become \(1/2\)
$O ^{2-}, F ^{-}, Al , Mg ^{2+}, Na ^{+}, O ^{+}, Mg , Al ^{3+}, F$