The f-block elements, also known as inner transition elements, consist of the lanthanides (atomic numbers 57–71) and actinides (atomic numbers 89–103). They are characterized by the filling of the 4f and 5f orbitals, respectively.
These elements are typically found at the bottom of the periodic table and exhibit similar chemical properties due to their partially filled f-orbitals. Lanthanides are known for their magnetic and optical properties, while actinides are mostly radioactive.
Common applications include catalysts, phosphors, and nuclear energy. Due to their complex electronic configurations, f-block elements exhibit variable oxidation states and form colored compounds.
The f orbital of an element in the F block is filled with electrons. The f orbital (1 to 14), the d orbital (0 to 1) of the penultimate energy level, and the orbital of the outermost all have electrons.
The filling of 4f and 5f orbitals corresponds to two series in the f block. The Ce to Lu 4f series and the Th to Lw 5f series are the components. The ‘f’ orbital is filled with 14 elements in each series.
F Block Elements in the Periodic Table: F block elements are arranged at the bottom of the periodic table separately. They’re a combination of the 6th and 7th sessions.
The f block’s constituents are further classified as follows:
The first group of elements is the lanthanides, which include elements with atomic numbers ranging from 57 to 71. These are elements that are not radioactive (except for promethium, which is radioactive).
The second group of elements is the actinides, which consist of atoms with atomic numbers ranging from 89 to 103. The bulk of these substances is radioactive in nature.
The following is a list of all the f block elements. The row that starts with Lanthanum contains all of the lanthanides, while the row that starts with Actinium has all of the actinides.
In terms of transition metal naming, f block elements are referred to as inner transition elements since the f orbital is significantly closer to the centre than the d orbital.
Lanthanides and other f-block chemical elements operate as active metals. As a result, these elements’ redox reaction potential is comparable to that of alkaline earth metals. All of the metals in the f-block act as powerful reducing agents, releasing hydrogen ions in chemical reactions with acids. Interstitial hydrides are formed when they absorb hydrogen ions from low pH scale fluids.
Although there are significant parallels between the two series of F-block parts, there are also significant differences. These discrepancies occur because 5f block elements have lower bond energies, ionisation energies, and less effective shielding electrons than 4f block elements. With increasing atomic numbers, the conventional electrode potentials for f-block lanthanides become increasingly positive. However, from actinium to uranium, electrode potentials increase more positive, then less positive until Americium.
Lanthanides and Actinides have a lot in common.
The filling of the (n-2) f subshell distinguishes the elements of the lanthanide and actinide series. They have nearly identical outermost electrical configurations and, as a result, have similar characteristics. The following are some notable parallels:
Lanthanide electronic configuration
Lanthanides have a general valence shell electronic configuration of [Xe] 4f0, 2 to 14 5d0 to 1 6s2. As a result, the electronic configuration of praseodymium’s valence shell is [Xe] 4f3 5d0 6s2.
The components are the Ce to Lu 4f series and the Th to Lw 5f series. In each series, the 'f' orbital is filled with 14 elements. The Periodic Table's Position of F Block Elements: The elements of the F block are listed separately at the bottom of the periodic table.
The name f- blocks comes from the fact that the last electron enters the anti-penultimate shell's f-orbital. Inner transition elements are another name for these. The f block has two series that correspond to the filling of 4f and 5f orbitals. In most cases, the transition elements have an unfilled d-orbital.