Question

Identify the following substances as paramagnetic, diamagnetic or ferromagnetic
(i) Sodium-${\text{Na}}$
(ii)Magnesium-${\text{Mg}}$
(iii) $_{20}C{a^{2 + }}$ cation
(iv) $_{17}C{l^{ - \,\, - }}$ anion
(v)Iron$_{26}Fe$
(vi) $_{27}Co$ atom
(vii) $_{28}Ni$ atom

Answer 1

When a substance is placed in a magnetic field, they show different magnetic behavior. On the basis of this behavior, substances are classified as paramagnetic, diamagnetic, ferromagnetic, ferrimagnetic, anti-ferromagnetic etc.

Complete step by step answer:
We know that,
Na has electronic configuration $\left[ {{\text{Ne}}} \right]{\text{3}}{{\text{s}}^{\text{1}}}$,that is it contains one unpaired electron. So, it is paramagnetic in nature
Mg electronic configuration $\left[ {{\text{Ne}}} \right]{\text{3}}{{\text{s}}^2}$. It has all electrons paired so it is diamagnetic in nature.
${\text{C}}{{\text{a}}^{{\text{2 + }}}}$ on losing 2 electrons, behaves as an inert gas. So, diamagnetic in nature.
${\text{C}}{{\text{l}}^{2 - }}$ anion after accepting 2 electrons, behaves as alkali metal. So, it is paramagnetic in nature.
$_{26}{\text{Fe,}}{\,_{27}}{\text{Co}}$ and $_{_{{\text{28}}}{\text{Ni}}}$ are all ferromagnetic in nature. It is because, when we place these elements in a magnetic field at room temperature, they align themselves with respect to that of the external magnetic field. This alignment does not change even when the external magnetic field is removed. That is, they exhibit permanent magnetism.

Additional information:
There are various effects of temperature on the paramagnetic, diamagnetic, ferromagnetic substances. Some of the are:

1. ${\text{F}}{{\text{e}}_{\text{3}}}{{\text{O}}_{\text{4}}}$ at ordinary temperature is ferrimagnetic but at ${\text{850}}\,{\text{k}}$ it shows paramagnetic character.
2. ${{\text{V}}_{\text{2}}}{{\text{O}}_{\text{3}}}$ at ${\text{150}}\,{\text{k}}$ transforms from the anti-ferromagnetic state to the paramagnetic state.
3. ${\text{NiO}}$ at ${\text{395}}\,{\text{K}}$ transforms from the anti-ferromagnetic state to the paramagnetic state.
4. ${\text{Cr}}{{\text{O}}_{\text{2}}}$ at ${\text{395}}\,{\text{K}}$ transforms from the anti-ferromagnetic state to the paramagnetic state.

Note: The electrons revolving around the nucleus, exhibits two types of motion. These motions are orbital motion and spin motion. Both these motions generate magnetic fields when a substance is placed in between the poles of a horseshoe magnet.