Question

Which of the following substances is paramagnetic?
$Bi,Al,Cu,Ca,Pb,Ni$

Answer 1

The atoms which contain unpaired electrons are known as paramagnetic substances. The atoms which do not contain unpaired electrons are known as diamagnetic substances. The net dipole moment is an important factor that leads to the determination of the magnetic nature of elements.

Complete answer:
Chemical elements are the purest form of atoms and cannot be separated by any chemical action. An atom contains subatomic particles like electrons, protons, and neutrons. If the spin of the electrons is in the same direction, then they are known as unpaired electrons. If the spin of the electrons is exactly opposite in the same subshell, then it is completely filled and does not have any spin magnetic moment.
Given elements are bismuth, aluminum, copper, calcium, lead, and nickel.
When the elements or molecules that were attracted in presence of a magnetic field are known as paramagnetic substances.
When the elements or molecules that were repelled in presence of a magnetic field are known as diamagnetic substances.
Out of these elements, aluminum and calcium have the dipole moment and have the presence of unpaired electrons. Due to the presence of unpaired electrons, these two are considered paramagnetic substances.

Note:
There is another type of magnetic substance which is known as ferromagnetic substances. These are strongly attracted in presence of the magnetic field. Some of the elements that act as ferromagnetic substances are iron, cobalt, and nickel. Some alloys can also act as ferromagnetic substances.