Why is iron magnetic but copper isn't?

Iron is magnetic because of its electron configuration which allows for unpaired electrons, unlike copper which has all paired electrons.

Iron is magnetic due to its particular electron configuration, which results in unpaired electrons. These unpaired electrons are free to align themselves in response to a magnetic field, which is what gives iron its magnetic properties. This is a result of the atomic structure of iron, which has 26 electrons arranged in a specific way. The outermost shell of an iron atom has two electrons in one subshell and four in another, which means there are unpaired electrons that can align with a magnetic field.

On the other hand, copper is not magnetic because its electron configuration results in all electrons being paired. Copper has 29 electrons, and in its ground state, these electrons are all paired up in the atomic orbitals. This means that there are no unpaired electrons that can align with a magnetic field, which is why copper is not magnetic.

The magnetic properties of a material are determined by its atomic structure, specifically the configuration of its electrons. In materials like iron, the presence of unpaired electrons allows for the alignment with a magnetic field, which results in the material being magnetic. In contrast, materials like copper, where all electrons are paired, do not have this ability to align with a magnetic field and are therefore not magnetic.

This is a fundamental concept in the study of magnetism and materials science. It's important to note that not all metals are magnetic, and the magnetic properties of a material are not solely determined by whether it is a metal or not. Instead, it's the specific arrangement and behaviour of the electrons within the atoms of the material that determine whether it is magnetic or not.