Boron is a good semiconductor because it is a semimetal, while other Group 3A elements are good conductors because they are metals.

Boron only forms molecular compounds due to its high ionization energy, while the other 3A elements form ionic compounds due to their lower ionization energy.

Boron has a higher melting point due to its smaller atomic radius, while the other Group 3A elements have a lower melting point due to their larger atomic radii.

All of the above