Answer:
A substance that has paired electrons - diamagnetic
A substance that has unpaired electrons - paramagnetic
A substance that has no net magnetic moment - diamagnetic
A substance that is attracted to an external magnetic field - paramagnetic
A substance that is weakly repelled by external magnetic field- diamagnetic
Explanation:
Mostly in all atoms of a substance, the electrons are found in pairs and these electrons spin in opposite directions. When this substance is placed inside an external magnetic field, the opposite spins of paired electrons cancel their magnetic fields and so, no net magnetic field exists. If a substance with some unpaired electrons is placed inside an external magnetic field, the unpaired electrons will have a net magnetic field. The magnetic properties of an atom depend on the electron spin in that atom. Based on this, substances can be classified as diamagnetic, paramagnetic or ferromagnetic.
Diamagnetic materials - They are materials with paired electrons or diamagnetic electrons and their electron spins get canceled. So, their total spin is zero and gets repelled slightly by an external magnetic field. The net magnetic moment is absent in such materials. The examples of diamagnetic materials include most elements in the periodic table such as gold, copper, silver, etc.
Paramagnetic materials - They are materials with unpaired electrons or paramagnetic electrons and are attracted by an external magnetic field. In such materials, the entire atom will have a net spin. Examples of paramagnetic materials include lithium, magnesium, tantalum, molybdenum, etc.
Ferromagnetic materials - They are materials with some unpaired electrons and so they are strongly attracted to an external magnetic field. Their atoms have a net magnetic moment and have the ability to retain their magnetic properties even after the removal of the external magnetic field. Examples of ferromagnetic materials include cobalt, nickel, iron, etc.
