Why can't copper be made into a magnet?
Magnetism results from the alignment of an atom's outer electrons. There are three types of magnetism:
- Diamagnetism-atoms that have no unpaired outer electrons are repelled by a magnetic field.
- Paramagnetism-atoms that have unpaired electrons are attracted to a magnetic field. These two types of magnetic forces are only observable in the presence of a magnetic field.
- Ferromagnetism - exists in some atoms with unpaired d-electrons and results in permanent magnetic domains that are strong enough to be detected.
Of the three, only ferromagnetism is permanent. Iron, nickel, cobalt and some of the rare earth elements are ferromagnetic.
Copper is diamagnetic because of its electron configuration:
[Ar] 3d10 4s1
The 3d orbital is filled before the 4s because a full sub-level of electrons creates stability. The d-orbital can hold a maximum of 10 electrons, so copper has no unpaired d-electrons.
Magnets can be made from substances that have permanent magnetic domains. Exposing the substance to a strong magnetic field while it's in a molten state will cause the magnetic domains to line up in the same direction and then stay that way when the substance solidifies. Pure copper can't be made into a magnet because it doesn't have these magnetic domains. However, scientists have been able to create a magnet by alternating layers of copper with layers of carbon. The carbon must be in a special form called a buckyball.