A \[\ce{_{25}Mn^{2+}}\] y \[ \ce{_{26}Fe^{3+}} \] B \[\ce{_{20}Ca}\] y \[\ce{_{22}Ti^{2+}}\] C \[\ce{_{38}Sr} \] y \[ \ce{_{40}Zr^{2+}} \] D \[\ce{_{24}Cr}\] y \[\ce{_{27}Co^{3+}}\] E \[ \ce{_{19}K} \] y \[ \ce{_{21}Sc^{2+}}\]