The element having general electronic configuration $3d^4 4s^1$ is

The correct order of ionic radii for $Y^{3+}$,$La^{3+}$,$Eu^{3+}$,and $Lu^{3+}$ is:

$Mn, Co, Cu$ metals form useful alloys because:

The atomic number of $Pd$ is $46$. The atomic numbers of the elements lying immediately above and below it in the same group are,respectively,.....................

The higher number of unpaired electrons are in

$Ce^{4+}$ is stable. This is because of