Question

Of Cobalt and Zinc salts, which are attracted in the magnetic field?
A. Cobalt salts
B. Zinc salts
C. both (A) and (B)
D. None of these

Answer 1

The decay rate of any substance is directly proportional to the activity of the substance or the initial concentration of the reactant. The half life of any substance is inversely proportional to the decay rate constant of the reaction.

Complete answer:
The atomic number of cobalt is 27 and that of zinc is 30. The electronic configuration of cobalt is as follows:
$Co = [Ar]4{s^2}3{d^7}$
The electronic configuration of cobalt shows that it has three unpaired electrons which have their own spin and produce a magnetic moment. This magnetic moment interacts with the external magnetic field and applies an attractive force on the cobalt atom. Thus, the salts of cobalt are attracted by the external magnetic field. The magnetic moment generated in these salts is calculated in terms of Bohr magneton.
The electronic configuration of zinc is as follows:
$Zn = [Ar]4{s^2}3{d^{10}}$
As there are no unpaired electrons present in the zinc atom, the interaction of the atom with the magnetic field will be zero and thus the salts of zinc are not attracted by the magnetic field.

So, the correct answer is Option A.

Note:
The greater the number of unpaired electrons in the valence shells of the atom, the grater the magnetic spin and the greater the magnetic moment will be. Due to this, the magnetic force of attraction and repulsion will also be more on the particular atom.