Question

What are elements $89$ to $103$ called?

Answer 1

Elements from atomic number $89$ to $103$:

• These are the elements placed in the separate block from the D- block elements which are known as F-block elements.
• Their valence shell electron enters the f-orbital.

f-Block elements:

• Lanthanoids and actinoids are the two series into which the F block of elements is separated.
• Because they create a transition in the sixth and seventh row of the periodic table that separates the s block and the d block elements, this group of elements is frequently referred to as the “inner transition metals.”
• These elements form the given atomic number $89$ to $103$ come under the actinides group.
• Actinides are a group of 15 elements with atomic numbers ranging from 89 to 103. Actinium$\left(\mathrm{Ac}\right)$, the initial component in the series, inspired their names.

Actinides:

• Actinium, the series' initial element, is whence the phrase "actinide series" originates.
• Any element in the actinide series, which has an atomic number between $89\mathrm{and}103$ on the periodic table, is denoted by the symbol$\mathrm{An}$.
• All elements in the actinide series are radioactive by nature; when they decay, a significant quantity of energy is released.
• The most prevalent naturally occurring actinides on earth are uranium and thorium, while plutonium is produced artificially.

Physical properties of Actinides:

• Density- All actinides have relatively high densities, with the exception of thorium and americium.
• Melting and Boiling Point: Like lanthanides, actinides have relatively high melting points, although there is no clear pattern in the melting or boiling points of lanthanides.
• Magnetic Properties: The paramagnetic character of all actinides depends on the existence of unpaired electrons. The shielding of the $5\mathrm{f}$ electrons causes the orbital angular moment to be quenched, resulting in a difference between the calculated and observed magnetic moments.