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

What are actinoids? Give three examples.

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

Write the general outer electronic configuration of f- block elements.

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

Which of the following lanthanoid ions is diamagnetic?

What are inner transition elements?

Compare lanthanoids and actinoids.

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.

The element with atomic number 57 belongs to ______.