Group 13 Elements

Boron, Aluminium, Gallium, Indium and belong to IIIA group of the Periodic table. The general outer electronic configuration of IIIA group elements is ns2np1.

B and Al show similar properties due to similar outer electronic configuration. They show differences in some of the properties due to the difference in the number of electrons present in their penultimate shells.

Boron is a non metal. Al , Ga, In, and are metals.

Atomic radius increases suddenly from B to Al. This is due to the greater screening effect of electrons present in the penultimate shell. The atomic radii of Al and Ga are same. This is because of the poor shielding effect of d-electrons in Gallium.