Which of the following is the characteristic outer electronic configuration of alkaline earth metals?

$A$ heavy nucleus at rest breaks into two fragments which fly off with velocities in the ratio $3: 1$. The ratio of radii of the fragments is

The yellow colour solution of $Na_2CrO_4$ changes to orange-red on passing $CO_2$ gas due to the formation of

Observe the following statements :
$I$. The physical and chemical properties of elements are periodic functions of their electronic configuration.
$II$. Electronegativity of fluorine is less than the electronegativity of chlorine.
$III$. Electropositive nature decreases from top to bottom in a group.
The correct answer is :

The name of the complex ion,$[Fe(CN)_6]^{3-}$ is:

$A$ charge '$q$' is spread uniformly over an isolated ring of radius '$R$'. The ring is rotated about its natural axis with angular speed $\omega$. The magnetic dipole moment of the ring is