Boron is non-magnetic because it lacks unpaired electrons in its atomic structure. Unpaired electrons are necessary for materials to exhibit magnetic properties, as they create tiny magnetic fields that interact with each other.

Boron has an atomic number of 5, meaning it has five electrons. These electrons are arranged in its atomic orbitals in the following configuration: 1s^2 2s^2 2p^1.

As you can see, the 2p orbital has only one electron. This means there are no unpaired electrons in boron's atomic structure. When a magnetic field is applied to a material, the unpaired electrons will align themselves either parallel or antiparallel to the field. This alignment creates a net magnetic moment, which is what gives rise to magnetism.

Because boron has no unpaired electrons, it cannot align its electrons in a magnetic field and therefore does not exhibit any magnetic properties. This is why boron is considered to be a non-magnetic material.