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D & F-BLOCK ELEMENTS in 1 Shot - All Concepts with PYQs | Class 12 NCERT

NCERT Wallah・94 minutes read

Ayush Kumar Gupta's chapter on Tongue Twisters focuses on the D and P block elements in Organic Chemistry, emphasizing the significance of electronic configurations and oxidation states in transition elements, which exhibit variable oxidation states and unique properties crucial for various chemical reactions. The chapter also highlights the importance of understanding hydration energy and the behavior of unpaired electrons to predict the reactivity and characteristics of these metals in chemical processes.

Insights

  • Ayush Kumar Gupta introduces the chapter by emphasizing the significance of understanding electronic configurations and oxidation states in D and P block elements, while noting the removal of topics like KMnO4 and Cr2O7, which are essential for grasping these concepts in organic chemistry.
  • The chapter highlights that transition elements, characterized by incomplete d orbitals, exhibit common oxidation states, particularly +2, and are defined by their electronic configurations, with specific examples provided to illustrate the configurations of elements like Scandium and Copper.
  • The text explains the relationship between atomic size and effective nuclear charge, detailing how atomic size decreases across periods due to increasing nuclear charge, and discusses the implications of this trend on ionization energy and the challenges of electron removal from stable configurations in the D block series.
  • The importance of hydration energy in chemical reactions is underscored, particularly for transition metals like copper, where the energy dynamics of hydration significantly influence their oxidation states and reactivity, highlighting the need for a comprehensive understanding of these elements in various chemical processes.

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Recent questions

  • What are transition metals?

    Transition metals are elements found in the d-block of the periodic table, characterized by their ability to form variable oxidation states and incomplete d orbitals. They typically exhibit properties such as high melting points, the ability to form colored compounds, and magnetic properties. Transition metals include elements like iron, copper, and nickel, which are known for their reactivity and ability to form complex ions. Their electronic configurations play a crucial role in determining their chemical behavior, making them essential in various industrial and chemical processes.

  • How do oxidation states work?

    Oxidation states refer to the degree of oxidation of an atom in a chemical compound, indicating how many electrons an atom has gained, lost, or shared during a reaction. Transition metals are particularly notable for exhibiting multiple oxidation states, which can range from +1 to +7, depending on the element and its chemical environment. For instance, manganese can show oxidation states from +4 to +7, influencing its reactivity and the nature of the compounds it forms. Understanding oxidation states is crucial for predicting the behavior of elements in chemical reactions and their interactions with other substances.

  • What is effective nuclear charge?

    Effective nuclear charge (Z - σ) is a concept in chemistry that describes the net positive charge experienced by an electron in a multi-electron atom. Here, Z represents the atomic number, while σ denotes the shielding effect caused by inner electrons that reduce the attraction felt by outer electrons towards the nucleus. As one moves across a period in the periodic table, the effective nuclear charge generally increases, leading to a decrease in atomic size. This concept is essential for understanding trends in atomic properties, such as ionization energy and electronegativity, as it directly influences how tightly electrons are held by the nucleus.

  • What is hydration energy?

    Hydration energy is the energy released when ions are surrounded by water molecules, a process crucial for many chemical reactions involving soluble salts. For example, when copper ions are hydrated, significant energy is released, which affects their stability and reactivity. The amount of hydration energy can vary depending on the size and charge of the ion; smaller and more highly charged ions typically release more energy upon hydration. Understanding hydration energy is vital for predicting the behavior of ions in solution, their solubility, and their interactions with other chemical species.

  • What are the properties of transition metals?

    Transition metals possess several distinctive properties that set them apart from other elements. They typically have high melting and boiling points, exhibit variable oxidation states, and can form colored compounds due to the presence of unpaired electrons in their d orbitals. Additionally, many transition metals are good conductors of electricity and heat, and they often form complex ions with ligands. Their ability to form alloys and interstitial compounds further enhances their utility in various applications, from construction materials to catalysts in chemical reactions. Understanding these properties is essential for leveraging transition metals in industrial and scientific contexts.

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Summary

00:00

Understanding D and P Block Elements

  • Ayush Kumar Gupta introduces the chapter on Tongue Twisters, focusing on Block Elements in Organic Chemistry, specifically the D and P block elements and their electronic configurations.
  • The chapter discusses the deletion of certain topics, including KMnO4 and Cr2O7, and emphasizes the importance of understanding oxidation states and electronic configurations.
  • D block elements are defined by their last electron entering the d orbital, with a focus on the electronic configurations of transition elements.
  • The text explains the classification of elements into groups, specifically noting that there are 10 groups in the D block, ranging from group 3 to group 12.
  • Transition elements are characterized by incomplete d orbitals and common oxidation states, typically showing +2 oxidation states in reactions.
  • The electronic configuration of transition elements is crucial, with examples provided for elements like Scandium (Ar 18 3d1) and Copper (Ar 18 3d10 4s1).
  • The chapter highlights the significance of understanding the properties of transition elements, including their magnetic properties and color.
  • It emphasizes the need to memorize electronic configurations for elements up to Zinc, as they are foundational for understanding transition elements.
  • The text discusses the distinction between true transition elements and pseudo-transition elements, clarifying that the latter do not have incomplete d orbitals.
  • Finally, the chapter outlines the importance of recognizing the properties and behaviors of transition elements in chemical reactions, particularly in relation to their oxidation states.

24:03

Understanding Transition Elements in Chemistry

  • The text discusses the periodic table, specifically focusing on the transition elements, which are located in the D block and include 32 elements in total.
  • Transition elements are defined by their electronic configuration, typically involving the filling of d orbitals, with a general configuration of (n-1)d^1-10.
  • The first series of transition elements spans from scandium (atomic number 21) to zinc (atomic number 30), covering the 3D series.
  • The second series includes elements from yttrium (atomic number 39) to cadmium (atomic number 48), representing the 4D series.
  • The third series consists of elements from lanthanum (atomic number 57) to mercury (atomic number 80), known as the 5D series.
  • Key properties of transition elements include variable oxidation states and the ability to form colored compounds, which are essential for various chemical reactions.
  • The text emphasizes the importance of memorizing the atomic numbers and configurations of these elements for academic success, suggesting mnemonic devices for easier recall.
  • Specific examples of transition elements include nickel, copper, and palladium, with their configurations detailed for clarity.
  • The text also mentions the significance of understanding electron removal in ionization, particularly for elements like copper and palladium.
  • Overall, the content serves as a guide for students to grasp the structure and properties of transition elements in the periodic table.

49:59

Understanding d-Block Elements and Atomic Size Trends

  • Configuration 21 to 30 requires tips on physical properties, particularly focusing on oxidation in the d-block elements, which are characterized by their unique properties and behaviors.
  • All metals in the d-block are referred to as family forces, capable of being transformed into thin sheets, with mercury being the only liquid metal at room temperature.
  • Mercury can be utilized to create allocated block elements through substantial heat and electricity, exemplified by the production of silver and copper wires, which are excellent conductors.
  • Iron is highlighted for its strength and utility in construction, with its properties making it suitable for building robust structures that are shiny and sonorous.
  • The text discusses the significance of atomic size, emphasizing that as one moves left to right across periods, atomic size generally decreases due to increasing nuclear charge.
  • Effective nuclear charge (Z - σ) is introduced, where Z represents the atomic number and σ denotes the shielding effect, impacting how valence electrons experience attractive and repulsive forces.
  • The shielding effect is explained as a barrier formed by inner electrons that reduces the attraction felt by outer electrons towards the nucleus, influencing atomic size.
  • The relationship between atomic size and effective nuclear charge is clarified, indicating that a higher effective nuclear charge results in a smaller atomic size due to increased attraction.
  • The text outlines the trends in atomic size across the 3D and 4D series, noting that atomic size generally decreases from left to right, with specific examples like chromium, iron, and nickel.
  • Finally, the concept of length contraction is introduced, explaining how atomic size can be affected by electron filling and the screening effect, particularly in elements like mercury.

01:12:42

Understanding Size and Charge in Elements

  • Five mistakes were identified and removed from the chart regarding the relationship between social increase and size increase in elements, particularly in 5D elements.
  • The size of the 5D element is approximately 240, with a noted size of 253, indicating a significant size consideration in the chart.
  • Contractions are discussed, with a specific mention of 9 inches as the length reached during certain processes, emphasizing the importance of contraction in size.
  • The relationship between positive charge and size is highlighted, stating that greater positive charge generally results in a smaller size for elements like magnesium and iron.
  • The text mentions that as atomic numbers increase, the size of elements typically decreases, with specific examples from the periodic table illustrating this trend.
  • The concept of ionization energy is introduced, noting that as size decreases, ionization energy increases, with a specific increase of 100 units from left to right in the periodic table.
  • The irregularities in size trends within the D block series are noted, particularly how size can initially decrease before increasing again, complicating predictions.
  • The text emphasizes the difficulty of removing electrons from elements with stable electronic configurations, particularly in the 3D series, requiring significant energy.
  • Transition metals are discussed, with a focus on variable oxidation states, particularly how elements like scandium and zinc exhibit different oxidation states.
  • The electrode potential of the 3D series is analyzed, noting irregular trends and the importance of understanding these trends for applications in electrochemistry.

01:35:48

Energy Dynamics and Properties of Metals

  • Metals exist in a solid state, and to remove electrons, energy must be supplied, which is referred to as sublimation energy.
  • The process of sublimation allows a substance to transition directly from solid to gas without becoming liquid, requiring specific energy input.
  • Hydration energy is crucial for reactions involving metals; for example, copper requires hydration energy to change its oxidation state effectively.
  • Copper has two electrons that can be removed, changing its properties; this process involves understanding the energy dynamics of hydration.
  • The energy required for reactions can vary significantly; for instance, a higher hydration energy is needed for certain transformations, such as converting copper to copper ions.
  • The density of metals increases from left to right in the periodic table, influenced by atomic size and mass, affecting their physical properties.
  • The strength of metallic bonds is directly proportional to the number of unpaired electrons; more unpaired electrons result in stronger bonds and higher melting points.
  • Transition metals, like chromium, can exhibit multiple oxidation states, which is essential for their reactivity and ability to form complexes.
  • The electronic configuration of metals, such as chromium and nickel, plays a significant role in their chemical behavior and the energy required for electron removal.
  • Understanding the properties of transition metals, including their ability to form complexes and their varying oxidation states, is vital for applications in chemical processes.

02:00:53

Chemical Properties and Behavior of Transition Metals

  • Polymers are essential in creating polythene; use any potato except the specified type, and apply high temperatures for effective results in polymerization processes.
  • The color of compounds is influenced by unpaired electrons; for example, potassium permanganate exhibits a pink-purple hue due to its electronic structure.
  • Transition metals like silver bromide and iodide display distinct colors; silver iodide appears yellow due to polarization effects during electron transfer.
  • Polarization increases with smaller ionic sizes; for instance, silver chloride turns white when chloride ions are small, indicating a strong polarizing effect.
  • Alloys, such as steel (iron plus carbon), are created by mixing metals with size differences of no more than 15% to ensure compatibility and stability.
  • Interstitial compounds form when smaller atoms occupy spaces in metal lattices; nitrogen can fit into transition metal structures, enhancing their properties.
  • The oxidation states of transition metals vary; for example, manganese can exhibit oxidation states from +4 to +7, influenced by surrounding elements like fluorine.
  • Copper's oxidation state can change; copper(I) iodide is unstable, while copper(II) can reduce to copper(I) through reactions with reducing agents.
  • Hydration energy plays a crucial role in copper's behavior; when copper(II) ions are hydrated, significant energy is released, affecting their stability.
  • Understanding the electronic configurations and properties of transition metals is vital for predicting their chemical behavior and reactivity in various applications.

02:24:03

Hydration Energy and Oxidation States in Copper

  • The text discusses the hydration energy of copper, specifically comparing Copper Two Plus and Copper Plus, emphasizing the significant energy release during hydration processes.
  • It mentions that Copper Plus requires the removal of cholesterol, indicating a chemical reaction where energy is released, quantified as 500 units.
  • The text highlights the importance of oxidation states, particularly manganese, which can exhibit a highest oxidation state of plus seven, affecting its chemical behavior.
  • It explains that as oxidation states increase, the acid character of the compounds also increases, suggesting a correlation between oxidation and acidity.
  • The discussion includes the reactivity of transition metals, noting that copper does not react with dilute acids due to its position in the reactivity series below hydrogen.
  • It details the electronic configurations of transition metals, emphasizing the significance of unpaired electrons in determining chemical properties and reactivity.
  • The text outlines the concept of lanthanide contraction, explaining how atomic size decreases across the series due to increased nuclear charge and shielding effects.
  • It mentions the common oxidation states of transition metals, particularly noting that many exhibit oxidation states of plus two and plus three.
  • The text emphasizes the similarity in physical and chemical properties among elements in the same group, particularly in relation to their atomic radius and reactivity.
  • Finally, it concludes with a summary of the oxidation states and properties of transition metals, reinforcing the importance of understanding these concepts in chemistry.

02:46:51

Electrons Hydration Energy and Chemical Reactivity

  • The text discusses the behavior of electrons in noble gases and transition elements, emphasizing that the release of two to four electrons affects their electronic configuration and reactivity.
  • It highlights the significance of hydration energy in chemical reactions, particularly in nickel and chromium, noting that changes in oxidation states influence electron removal and energy dynamics.
  • The importance of understanding concepts and numerical data in chemistry is stressed, with references to specific examples like copper ionization and the need for clarity in oxidation state experiments.
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