Question

What is ferromagnetism ? Iron $(z = 26)$ is strongly ferromagnetic. Explain.

Answer 1

Hint: The substance in which each individual atom/molecule has a zero magnetic moment. These materials get magnetized in the direction of the magnetic field. These materials are known as ferromagnetic substances.

Complete step by step answer: Let us understand about ferromagnetic substances. Ferromagnetism is those in which each individual atom/molecule has a zero magnetic moment. When substances are placed in an external magnetizing field, they get strongly magnetized in the direction of the field. The ferromagnetic substances have a strong tendency to move from a region of weak magnetic field to the region of strong magnet. Relative magnetic permeability of ferromagnetic materials is very large. The susceptibility of ferromagnetic materials is also very large that is why they can be magnetized easily and strongly. The magnetism of ferromagnetic substances is known as ferromagnetism.
Iron $\left( {z = 26} \right)$ contains unpaired electrons. When it is placed in the external magnetic field, unpaired electrons become parallel to the direction of the magnetic field even on the removal of the magnetic field. This means that iron gets permanently magnetized in the direction of magnetic field and thus is a ferromagnetic substance naturally.

Note: There are two more types of magnetic substance :- paramagnetic and diamagnetic.
Diamagnetic substances are the substances which do not contain any unpaired electrons that get very feebly magnetized in direction opposite to the magnetizing field . Paramagnetic substances are those in which each individual atom/molecule/ion has a net non zero magnetic moment and gets feebly magnetized in the direction of the magnetizing field.