d- and f- Block Elements

The d-block is found at the centre of the periodic table. It contains elements of the 3-12 group. Here, the d orbitals get filled in each of the four long periods. The f-block, on the other hand, is found at the bottom of the periodic table. It includes elements in which the 4 f and 5 f elements are filled. The d-block and f-block elements are commonly termed ‘transition’ and ‘inner transition’ metals. 

The transition metals include four series – 3d (Sc to Zn), 4d (Y to Cd), 5d (La and Hf to Hg), and 6d (Ac and Rf to Cn). The inner transition metal includes two series – 4f (Ce to Lu) or lanthanoids, and 5f (Th to Lr) or actinides.  

Transition elements of the d-block

The periodic table’s larger middle sections are occupied by the d-block. You can spot it between the s- and p-blocks. All their transitional properties occur between the s-block that consists of highly reactive metallic elements and the p-block that has largely covalent elements. Moreover, the metallic elements of the s-block are known to form ionic compounds. 

Now, the transition elements or the d-block elements are the ones that have partially filled the d subshell. In other words, the differentiating electrons occupy the sub-shell of the d-block. The reason why they are called transition elements is that they show a transition in their properties from the s-block elements to the p-block elements. All of them have the same physical properties. 

The d-block includes four series that begin with constituting group 3 to group 12 (or group III B to II B). The electrons get added to the penultimate shell in the d-block, due to which it expands from 8 to 18 electrons. Typically, the d-block is incompletely filled by the transition elements. It is in Group 12 that the zinc group gets a d10 configuration, and thus, the d-block is complete in that position. 

However, the compounds of these elements are not typical and differentiate from each other. Three complete rows and a fourth incomplete row are made by the ten elements. The position of the incomplete row is further discussed along with the f-block elements. Precious metals like gold, silver, platinum, copper, iron, and nickel are included in these elements.

Inner transition elements of the f-block

As mentioned earlier, the f-block includes two series – lanthanides and actinides. Lanthanides refer to the 14 elements that follow the lanthanum. On the other hand, actinoids refer to the 14 elements that follow the actinium. Lanthanum also closely resembles the lanthanides and, hence, is studied with them as the symbol Ln. Similarly, the study of actinoids also includes actinium as another element. The lanthanides are known for having a unique property. They resemble each other more closely than any other transition elements present in the series. All of them have a single stable oxidation state. 

The chemistry of lanthanide helps examine the effects of small changes in size and nuclear charge, along with a series of similar elements. However, the chemistry related to the actinides is more complicated. That happens due to the massive occurrence of oxidation states in these elements. Moreover, their radioactive activities also create problems in the study. 

Lanthanides

The elements that are included in lanthanides are as follows:

• Lanthanum (La)
• Cerium (Ce)
• Praseodymium (Pr)
• Neodymium (Nd)
• Promethium (Pm)
• Samarium (Sm)
• Europium (Eu)
• Gadolinium (Gd)
• Terbium (Tb)
• Dysprosium (Dy)
• Holmium (Ho)
• Erbium (Er)
• Thulium (Tm)
• Ytterbium (Yb)
• Lutetium (Lu)

Given below are the primary characteristics of lanthanides:

1. The lanthanides include 15 primary elements along with the atomic numbers 57 to 71.
2. All elements included in the same have one valence electron that is present in the 5d shell.
3. The elements share common properties with lanthanum.
4. The lanthanides are silver-coloured, reactive metals.
5. The most stable oxidation state of lanthanide atoms is known to be +3. 
6. The lanthanides are also termed rare earth. It is difficult to separate these elements from each other. 

Actinides

The elements that are included in actinides are as follows:

• Actinium (Ac)
• Thorium (Th)
• Protactinium (Pa)
• Uranium (U)
• Neptunium (Np)
• Plutonium (Pu)
• Americium (Am)
• Curium (Cm)
• Berkelium (Bk)
• Californium (Cf)
• Einsteinium (Es)
• Fermium (Fm)
• Mendelevium (Md)
• Nobelium (No)
• Lawrencium (Lr)

Given below are the primary characteristics of actinides:

1. All the actinides are radioactive. They have no stable isotopes.
2. Actinides are also highly electropositive.
3. The metals included in the same tarnish easily when exposed to air.
4. Actinides are dense metals that have distinctive structures.
5. They release hydrogen gas after reacting with dilute acid or boiling water.
6. Actinide metals are mostly soft, and one can easily cut them with a knife.
7. The elements are ductile and malleable.
8. Actinides are further paramagnetic.
9. The elements are silver-coloured and remain solid at room temperature.
10. Actinides can be combined directly with non-metals. 

The main difference between d-block and f-block elements

There is one significant difference between d- and f-block elements. The d- block includes chemical elements whose electrons are filled to their d orbitals. On the other hand, the f-block includes chemical elements whose electrons are filled to their f orbitals. 

Conclusion

The above study material notes on d- and f-block elements summarise that all of them show some general trends and various differentiating properties. They also include some important elements that we usually come across in our daily lives. The most common examples are iron, zinc, copper, gold, platinum, etc. 

Some of them also form complex compounds that we get to use in our daily lives. Iron and steel are the most important elements found in this group. Most of the elements of d-block, including their compounds, are catalysts. The f-block group is divided into lanthanoids and actinoids that have their unique characteristics. Both the d-block and f-block elements hold different positions in the periodic table.