Answer
Please see the work below.
Work Step by Step
When an atom contains only paired electrons, it is said to be diamagnetic. Diamagnetic substances are slightly repelled in a magnetic field.
Beryllium with electronic configuration $1s^{2}2s^{2}$ is an example of a diamagnetic element.
When an atom contains at least one unpaired electron, it is said to be paramagnetic. Paramagnetic substances are strongly attracted in the presence of a magnetic field.
Boron with electronic configuration $1s^{2}2s^{2}2p^{1}$ is an example of a paramagnetic element.
During an electron pairing their spins cancel out and there will be no net spin.
