F Block in Periodic Table: Characteristics, Classifications, Properties, Electronic Configuration, Differences, and Uses

F Block Elements Overview

F block elements exist in two chemical series in the periodic table, such as 4 f block names as lanthanides or rare earth elements and 5f block names as actinides or actinides. The electrical arrangement of the f-block chemical elements (lanthanum and actinium) was created by filling electrons in deep-seated 4f and 5f orbitals with increasing atomic numbers. Every element in the f-block has a trivalent oxidation number or state, which is a stable or common oxidation state.

What is a Block in the Periodic Table of Chemistry?

A periodic table block is a group of elements linked together by the atomic orbitals in which their valence electrons or vacancies reside. Charles Janet appears to have coined the phrase. The blocks are designated by their respective orbitals: s-block, p-block, d-block, f-block, and g-block. The designations of the blocks (s, p, d, and f) are taken from the spectroscopic nomenclature for an electron's azimuthal quantum number-

1. Sharp (0)
2. Principal (1)
3. Diffuse (2)
4. Fundamental (3)

Following notations are in alphabetical sequences, such as g, h, and so on, however components that would belong in such blocks have yet to be discovered.

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What is F Block?

F-Block elements are those in which the final electron enters any of the seven f-orbitals of their respective ante-penultimate shells. These elements have electrons (1 to 14) in the f orbital, (0 to 1) in the d orbital of the penultimate energy level, and (0 to 1) in the outermost orbital. There are basically two series in the f-block that correspond to the filling of 4f and 5f orbitals. There are two sets of elements- the 4f series of Ce to Lu and the 5f series of Th to Lw. Each series has 14 components that make up the 'f' orbital.

Examples of F Block Elements

Cerium, gadolinium, and lutetium are atomic numbers 58, 64, and 87 in the periodic table, respectively, and have one electron in a 5d orbital. As a result, the electron configurations of cerium, gadolinium, and lutetium differ from the usual electrical configuration.

Characteristics of F Block Elements

The following are some of the characteristics of F Block elements-

1. Actinides are naturally radioactive.
2. As the atomic number increases, so does the atomic and ionic size.
3. Lanthanide oxides are used as abrasives in glass cleaning.
4. They are hefty and tough metals.
5. They are magnetic in nature.
6. They are very electropositive and extremely reactive.
7. They contribute to the filling of (n-2) f orbitals.
8. They have a propensity to generate complicated molecules.
9. They have high melting and boiling points in general.
10. They have varying oxidation states.
11. They produce colored ions.

Periodic Table Elements of F Block

The elements of the F-Block are typically found on the Periodic Table in two different horizontal rows that are fragmented and near the bottom of the table. Because of the location on the Periodic Table from where they are removed, the F-Block elements are sometimes referred to as "inner transition metals." If these elements could fit inside the Periodic Table, they would be in the transition metal region, between groups 2 and 3. They were eliminated so that the entire table would fit together better. By separating those two periods, elements in the table's remainder align with other components that have comparable attributes.

Read more about the First 20 Elements of the Periodic Table.

Classifications of F Block Elements

The F block's components are further subdivided into-

Lanthanides

Lanthanides, commonly known as lanthanides, are 15 successive chemical elements in the periodic table. This is obviously the periodic lanthanum through lutetium (atomic numbers 57-71), which includes rare-earth metals. Their atoms have comparable architectures and physical and behavioral characteristics, and the most common valencies are 3.

Actinides

Actinoids or actinides are 15 consecutive chemical elements in the periodic table; this is actinium, most likely periodic lawrencium (atomic numbers 89-­103). They are rather large for their radioactivity as a mixed bunch. Although many members in the squad, including uranium (more familiar), take place on a regular basis, the bulk is made up. Because of their volatile properties, uranium, and plutonium have both been utilized in atomic instruments. As a result, when it comes to the creation of electrical energy, they are used in atomic flowers.

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Properties of F Block Elements

The following are some of the properties of F Block elements-

1. The elements in this demonstrate that this is actinide radioactive, but the weather from atomic values 92 to 103 is both radioactive and manufactured.
2. These materials tend to produce vibrant icons. 
3. The second layer, which is the final transition, is filled with electrons. 
4. This is undeniably internal.
5. They are observed in F-Block elements with all the capacity to produce complex compounds, according to adjustable oxidation.

Lanthanide Group Properties

The lanthanide series includes elements with atomic numbers 57 to 71. These exchanges are not radioactive, and Promethium is the sole true exclusion. Within the components of these exhibits, the previous electron enters the 4f orbital. The following table gives details about some of the properties of the Lanthanide group of F Block-

Properties of Actinides

1. Actinide elements are used in atomic reactors and nuclear weapons. 
2. Actinides are common metals with characteristics similar to those of D and F block elements.
3. As a result, it is easy to get a clear understanding of how much heavier certain components typically are. 
4. Because of their massive magnitude, all of the elements in the series are unquestionably significant. 
5. The most important property of actinides is that they are generally radioactive. 
6. The present elements in this class range in atomic size from 227g/mol to 262g/mol. 
7. The small molecules are Alpha particles, microscopic particles similar to Gamma particles, and are radioactive.
8. Uranium and Thorium will have a variety of applications. 
9. When considering the actinides series, a few of the elements will also be employed as smoke detectors. 

Electronic Configuration of F Block Elements

The electrical configuration of f block elements (lanthanum and actinium series) is (n 2) f0, 2 to 14 (n 1) d0 to 2 ns2.

For example, the electronic configuration of the valence shell of the 4f block element promethium (atomic number 61) is 4f5 5d0 6s2.

Read more about the Electronic Configuration of the first 30 Elements.

F Block Elements: Difference between Lanthanides and Actinides

The following table gives the difference between Lanthanides and Actinides-

F Block Elements: Similarities between Lanthanides and Actinides

The following are some of the similarities between Lanthanides and Actinides-

1. As the atomic number increases, so do the atomic and ionic sizes.
2. Both have a pronounced +3 oxidation state.
3. The elements of the lanthanide and actinide series are distinguished by the presence of a (n-2) f subshell. 
4. They are very electropositive and extremely reactive.
5. They both have magnetic characteristics.
6. They contribute to the filling of (n-2) f orbitals.
7. They have almost identical outermost electrical structures and, hence, comparable characteristics.

Uses of F Block Elements

The following are some examples of how the f-block components can be used-

1. Lanthanide alloys (mischmetals) are used to make instrument steels and heat-resistant materials.
2. Lanthanide carbides, borides, and nitrides are examples of refractories.
3. Lanthanide oxides are used as abrasives in the polishing of glass.
4. Plutonium is required for both nuclear reactors and nuclear weapons.
5. Thorium is used in both incandescent gas lamps and cancer therapy.
6. Uranium is used to make nuclear fuel.

Points to Remember

1. Actinides are naturally radioactive.
2. F-block elements are known as inner transition elements because they provide a transition in the periodic table's sixth and seventh rows.
3. Lanthanides and actinides are the two series.
4. Lanthanides are non-radioactive in general.
5. The element block is known as an inner transition metal.
6. They are hefty metals.
7. They have high melting and boiling points in general. 

Sample Questions Related to F Block Elements 

Sample Question 1: Why is actinoid contraction stronger from element to element than lanthanoid contraction?

Solution: The actinoid contraction varies from element to element due to the weak shielding effect of 5F electrons compared to 4F electrons in lanthanide.

Sample Question 2: What is the last f-block element? 

Solution: Lawrencium (Lr) is the last element in the adenoids series, which is the second series of f-block elements.

Sample Question 3: Why are the lanthanides and actinides separated at the bottom of the periodic table? 

Solution: Lanthanides and actinides are separated at the bottom of the periodic table by the existence of 4f and 5f orbitals in lanthanoids and actinoids, respectively. Because of this, they are also known as internal transition elements. 

Sample Question 4: Why are the f-block elements grouped together? 

Solution: The f-block elements are separated from the main table primarily to save space. The table would have 32 columns if these components were added. 

Sample Question 5: Why are f-block components referred to as inner transition elements? 

Solution: Inner transition metal elements create a transition in the sixth and seventh rows of the periodic table, separating the s block and the d block elements.