NEET Study Notes for d and f block elements: d block elements are elements whose electrons are present in the d orbital. These are also known as transition elements. d block elements consist of four rows- with respect to filling 3d,4d,5d, or 6d orbitals. f block elements are also known as inner transition elements and their last electron is present in the f orbital. f block elements consist of 4f and 5f filling orbitals - which are Lanthanides and Actinides

• Inorganic chemistry has a weightage of around 34% in NEET Chemistry Syllabus. As per the previous year’s paper analysis, candidates can expect around 2-3 questions from d and f block elements.
• With sample questions and topic wise preparation, candidates will be able to prepare for d and f block elements for NEET 2022

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NEET Study Notes for d and f block elements: Important Topics

d block elements

The number of electrons present in the d orbital varies from 1 -10 while in the s orbital 1-2 in d block elements. D block elements possess characteristics like high conductivity, tensile strength, malleability, and ductility.

Electronic Configuration

The general electronic configuration of D block elements is (n-1)d^1-10ns^1-2. The elements with half-filled as well as completely filled d orbitals are stable.

Physical Properties of Transition Elements

Metallic character

All D-Block elements are metals and demonstrate characteristics like high malleability, electricity conductivity, heat conductivity, and ductility.

Atomic Radii

The atomic radii of transition elements decreases from Group 3 to Group 6. It remains stable from group 7 to 10 and increases from Group 10 to Group 12.

Ionization Enthalpy

Due to half-filled and fully filled stable elements of D group elements, I.E of these elements is also more. Ionization Enthalpy increases with an increase in atomic number rill Fe.

• In the second series, Copper and Ni share electrons, and thus despite the increase in atomic number, the Ionization Enthalpy decreases while copper and zinc have to increase Ionization Enthalpy.
• Palladium has a filled d shell. There are no electrons present in the s-shell. Thus palladium has the highest Ionization Enthalpy. 5d elements have higher I.E in comparison to 3d and 4d elements.

High melting and Boiling point

The high melting and boiling point of transition elements is high due to their strong bonding. The melting point increases and then decreases due to a decrease in the atomic number.

• Transition elements with high melting and boiling point are CR, Mo, and W while manganese a,d Technetium have low melting and boiling point due to their weak bonding.
• The lowest melting and boiling point in the series is of elements of Group 12, Zn, Hg, and Cd. The only element in this series that exists in a liquid state is Mercury.

Also Read:

• NEET Study Notes for p block elements
• NEET Study Notes for Polymers

Magnetic Properties

The relationship between transition elements and magnetic field gives rise to three magnetic properties of D elements:

1. Paramagnetic- The presence of unpaired electrons in d orbitals leads to the paramagnetic characteristic of d elements With the increase in the number of unpaired electrons, the paramagnetic characteristic also increases.
2. Diamagnetic - These are repelled..
3. Ferromagnetic- When magnetic characteristics are acquired by a substance.

While diamagnetism is due to the presence of paired electrons, paramagnetism is due to the presence of unpaired electrons, When such unpaired electrons are combined they give rise to ferromagnetism.

Oxidation State

• The losing or gaining of electrons to form a chemical bond is defined as the oxidation state. The electrons in the s and- d orbital of transitions element can form ionic as well as covalent bonds.

• Thus different oxidation states are observed. In lower oxidation states, ionic compounds are formed whereas, in high oxidation states, covalent bonds are formed. Transition elements like Cr, Cu, Ag, Au, and Hg have oxidation state 1.

Alloy Formation in D block elements

• Due to the small difference between transitions element’s atomic radii, solid solutions can be formed when such difference is within 15%.
• Such D block elements can form alloys. The alloys formed have a high melting point and tensile strength in comparison to the initial characteristics of the metal.
• Examples- Bronze, Chromium steel, Solder, Stainless steel.

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Interstitial compounds of D block elements

• There are spaces in the transition metals where small atoms and molecules of hydrogen, carbon can get trapped.
• These are called interstitial compounds- They do not have ionic, covalent, or non-stoichiometric characteristics.
• These compounds have high melting points and tensile strength. Their electrical conductivity is similar to other metals. They do not react and tend to be chemically inert. Examples-

Potassium Dichromate

• Potassium Dichromate is essential for chrome tanning, photography, and leather industries. Chromic acid is also used as a cleaning agent.
• The structure of potassium dichromate consists of two tetrahedra with a common chromium- oxygen- chromium bond.
• Potassium Dichromate is formed from chromite ore. Potassium Dichromate is orange in color. It has a melting point of 398∘ C and is soluble in water.

Potassium Permanganate

• Potassium Parmagnate is a dark purple substance with a melting point of 523 K . It is soluble in water.
• Potassium Permanganate is used as a disinfectant, oxidizing agent for oil decolorization, bleaching of cotton, silk, and wool.
• Potassium Permanganate is mainly prepared for manganese dioxide pyrolusite. Diamagnetic properties of potassium permanganate are observed as unpaired electrons are absent. Paramagnetic properties that depend on temperature are also observed, however, these are weak in nature.

Read:

• NEET Study Notes on Solid State
• NEET Study Notes for Aldehydes, Ketones and Carboxylic Acid

f block elements

The elements in which the last electron fills the f orbital or the inner transition elements. The number of electrons in these elements is-

F orbital- 1 to 14

D orbital (penultimate energy level and outermost shell)- 0 to 1

• F- block elements can mainly be classified into lanthanides and Actinides. That is equivalent to form 4f and 5f orbitals.
• Elements included in the 4f series are cerium to lutetium and in the 5f series from thorium to lawrencium.

Properties of f block elements

• Variable oxidation states are seen in F-Block elements with the tendency to form complex compounds.
• Colorful icons are formed by these elements. Electrons fill up the third last shell of these inner transition elements.
• The elements in the actinide series are radioactive whereas the elements from atomic numbers 92 to 103 are radioactive as well as synthetic.

Lanthanide Series

Elements from atomic numbers 57 to 71 are included in the lanthanide series. These inner transition elements are not radioactive in nature, the only exception is Promethium. In the elements of these series, the last electron enters the 4f orbital.

• Atomic Radius- Along with the lanthanide series, there is a decrease in the atomic radius. This is due to lanthanoid contraction. When the 4f orbital is not shielded properly, the outermost electron gets affected by the positive nuclear charge, which causes lanthanoid contraction and is eventually responsible for the decreasing atomic radius.
• Oxidation state- The oxidation state of lanthanoid varies. Generally, the oxidation state is +3 but it may be +4 and +2 due to the empty, fully filled, or partially filled f orbital.
• Metallic state- Lanthanide elements are generally metals. With the increase in atomic number, there is also an increase in the hardness of the metal. These are good conductors of electricity and heat.
• Electronic Configuration- The electronic configuration for Lanthanides 4f^1-145p⁶5d^0-16s² - from cerium to lutetium (z= 53 and 71 respectively)

Acitide Series

Elements from atomic number 89 to 103 are included in the Acitinde Series. They are radioactive. In the elements of this series, the last electron enters the 5f orbital.

• Atomic Radius- The atomic radius of Actinides decreases with a decrease in atomic number. This happened due to contraction.
• Oxidation state- The most common oxidation state is +3.but they are not always stable. Actinide series elements are highly reactive metals.

Uses of Inner Transition Elements

• The determination of rock and fossils is done by inner transition elements like Samarium and Lutetium.
• Inner transition elements like Uranium and Plutonium are used for nuclear weapon development and the generation of nuclear power plants.
• Lanthanides are useful in laser production and usage of strong, agents.
• Inner transition elements like Uranium protects against radiation.

NEET Sample MCQs for d and f Block elements

Question: Which of the following elements exhibit variable valency?

1. Alkaline Elements
2. Transition elements
3. Group Elements
4. Valence Elements

Answer: Transition Elements

Question: Actinode series contains elements from atomic number —

1. 89-102
2. 58-71
3. 89-103
4. 57-70

Answer: 89-103

Question: Which amongst the following element belongs to actinide series/

1. Cs
2. Ca
3. Ce
4. Cf

Answer: Cf

Question: Which among the following is not a transition element?

1. Re
2. Tc
3. Zr
4. Np

Answer: Np

Question: Californium element belongs to which series?

1. Alkaline Earth
2. Lanthanide
3. Actinide
4. Alkali

Answer: Actinide Series

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