Among the following components of cement,which is present in the highest amount?

The correct order of ionic radii of trivalent ions $Y^{3+}$,$La^{3+}$,$Eu^{3+}$,and $Lu^{3+}$ is $(Y=39, La=57, Eu=63, Lu=71)$.

Consider $|x|$ as the difference in oxidation states of Mn in the highest manganese fluoride and the highest manganese oxide. The ions with $|x|$ number of unpaired electrons from the following are: $A$. $Sc^{3+}$ $B$. $Zn^{2+}$ $C$. $V^{2+}$ $D$. $Fe^{2+}$ $E$. $Co^{2+}$ Choose the correct answer from the options given below:

Ferrous ion changes to $X$ ion upon reacting with acidified hydrogen peroxide. The number of $d$-electrons present in $X$ and its magnetic moment (in $BM$) are,respectively:

In which of the following compounds would the ionic radius of chromium be the smallest?

Which of the following elements show $+7$ oxidation states?