The last element of the p-block in 6th period is represented by the outermost electronic configuration.

Each period starts with the filling of electrons in a new principal energy shell. Therefore, 6th period starts with the filling of 6s-orbital and ends when 6p-orbitals are completely filled.In between 4f and 5d-orbitals are filled in accordance with aufbau principle. Thus, the outmost electronic configuration of the last element of the p-block in the 6th period is 6s2 4f14 6p6 or 4f14 5d10 6s2 6p6.