These elements are belongs to boron group which is thirteen group of periodic table. There are six elements are in this group boron, aluminium, gallium, indium, thallium and nihonium.
They are also called p-block elements because their valance electrons are present in p subshell.
All these elements have three valance electrons.
Boron is metalloid while other elements are metals.
Their oxidation state is +3 because of tendency to lose three valance electrons and create positive charge.
Their atomic sizes increases down the group with increase of atomic number.
Their ionization energies decreases down the group because of increase of atomic radius and ease of removing of electrons.
