Question

Explain the position of the following in periodic table
I.d-block elements
II.Lanthanide
III.Actinoide

Answer 1

We know that d-block elements are also known as transition elements (or) transition metals. The lanthanides and actinides are collectively called as the f-block elements. They are also known as inner transition elements. Lanthanoids and actinoids have magnetic properties.

Complete answer:
-d-block elements:
We know that d-block elements are found in the middle of the periodic table between s-block elements and p-block elements. D block elements are the elements which are present from the third group to the twelfth group of the modern periodic table. The outermost electrons of these elements come under the d orbital. The first three rows of the d block elements correspond to the $3d$,$4d$ and $5d$ orbitals respectively. A total of $10$ elements fills up the ‘d’ orbital in each series.
-Lanthanoids and Actinoids
F block elements are categorized into two series, lanthanoids and actinoids. These elements provide a transition in the ${6^{th}}$ and ${7^{th}}$ row of the periodic table which separates the s block and the d block elements and are called inner transition elements. There are two series in the f block corresponding filling up $4f$ and $5f$ orbitals. The elements that are present in $4f$ include $Ce$ to $Lu$ and $5f$ series of $Th$ to $Lw$. There are a total of $14$ elements occupying the ‘f’ orbital in each series.
F block elements are located separately at the bottom of the periodic table. F-block elements are a subset of 6th and 7th periods.

Note: We have to remember that the Lanthanides are found between Barium and Hafnium. Actinoides are found between Radium and Rutherfordium. Lanthanides include elements with atomic numbers starting from $57$ and ending at $71$. Actinides include elements with atomic numbers starting from $89$ and ending at $103$.