The Boron Family contains the semi-metal Boron (B) and metals Aluminum (Al), Gallium (Ga), Indium (In), and Thallium (Tl).
These elements are found in group 13 (XIII) of the p block in the Periodic Table of Elements. In their physical properties aluminum, gallium, indium, and thallium are metallic.
They have three electrons in their outermost shell (a full S orbital and one electron in the P orbital) with the valence electron configuration: ns2np1. The Boron Family has oxidation states +3 or +1. The +3 oxidation states are favorable except for the heavier elements, such as Tl, which prefers +1 oxidation state due to its stability. This is known as the inert pair effect. All the elements tend to follow Periodic Trends except Tl for particular trends, which is noted:Atomic Radius tends to increase going down the group (Tl has the largest atomic radius.)Electrode potential increases going down the group (reactivity decreases as going down group)Ionization Energy decreases going down the group (since the electrons are farther from the core and therefore are easier to remove)