Electronic Configurations - The f-Block Elements (Inner-transition Elements)

Why do zirconium and Hafnium exhibit similar properties?

The electronic configuration of gadolinium (Atomic number 64) is ______.

The actinoid elements which show the highest oxidation state of +7 are ____________.

Which of the following is not an actinoid?

In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz, s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each period begins with the filling of a new energy shell. In accordance with the Arfbau principle, the seven periods have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthanoids and actinoids are placed at the bottom of the main body of the periodic table.

Which of the elements whose atomic numbers are given below, cannot be accommodated in the present set-up of the long form of the periodic table?

Which of the following oxidation states is most common among the lanthanoids?

Actinoid contraction is greater from element to element than the lanthanoid contraction, why?

Justify the position of lanthanides and actinides in the periodic table.