Question

In group 13, the only metalloid, boron, is at the very top of the group. Explain why the rest of the group has metallic behavior but boron does not.

Answer 1

All the elements in group 13 have only 3 valence electrons, which means it is a little bit easier for them to lose those 3 electrons than it would be for them to gain 5 to form a full shell. However, it is also easier for elements with fewer electron shells to gain electrons. Since boron only has two electron shells, it is about as capable of gaining electrons as it is of losing electrons, so it behaves as a metalloid. The other elements in this group have more electron shells, so it is much easier for them to lose their valence electrons and they behave like metals.

Answer 2

Since it a metalloid it has metal and nonmetal properties while the rest of the group are all metals.