---
type: "Chapter"
knowledge_type: "chapter"
entity_type: "chapter"
id: "66def8373f8b4e9e69bda494"
title: "The d-and f-Block Elements"
board: "CBSE"
curriculum: "CBSE"
class: "Class 12"
subject: "Chemistry"
book: "Chemistry - I"
chapter: "The d-and f-Block Elements"
chapter_slug: "the-d-and-f-block-elements"
canonical_url: "https://www.edzy.ai/cbse-class-12-chemistry-chemistry-i-the-d-and-f-block-elements"
markdown_url: "https://www.edzy.ai/okf/chapter/cbse-class-12-chemistry-chemistry-i-the-d-and-f-block-elements.md"
source_type: "examSubjectBookChapter"
source_id: "66def8373f8b4e9e69bda494"
source_pdf: "https://edzy-ai.s3.ap-south-1.amazonaws.com/edzy-express-ts/750aebac-a7e6-43d2-a27d-95632292ae74.pdf"
source: "Edzy"
version: 1
last_updated: "2026-06-22"
---

# The d-and f-Block Elements
The d-block of the periodic table contains elements in which the d orbitals are progressively filled, while the f-block includes elements with progressively filled 4f and 5f orbitals. These elements are significant due to their unique properties and are categorized as transition metals and inner transition metals, respectively.

## Knowledge Snapshot

| Field | Details |
| :--- | :--- |
| Class | Class 12 |
| Subject | Chemistry |
| Book | Chemistry - I |
| Chapter | The d-and f-Block Elements |
| Pages | 89-118 |

## Chapter Summary

### Short Summary
The chapter covers the electronic configuration, properties, and applications of transition metals and inner transition metals, focusing on their unique characteristics due to partly filled d and f orbitals.

### Detailed Summary
The chapter elaborates on the positioning of d-block and f-block elements in the periodic table, defined by their electron configurations. It explains the grouping of transition metals across four series, the 3d, 4d, 5d, and 6d, and the two series of inner transition metals, lanthanoids and actinoids. Furthermore, it discusses how transition metals differ from non-transition elements due to their incomplete d subshell and highlights the importance of various transition metals in industrial applications.

## Topic-Wise Explanation

### Position in the Periodic Table
The d-block elements are located in groups 3-12, while the f-block elements are positioned separately at the bottom of the periodic table.

### Electronic Configurations
The general electronic configuration for these elements is (n−1)d1–10 ns1–2, with specific exceptions noted for some elements.

### General Properties of Transition Elements
Transition elements exhibit various unique properties, stemming from their partially filled d orbitals, which differentiate them from non-transition elements.

### Oxidation States
The oxidation states of these transition elements can vary, contributing to their diverse chemical reactivity.

### The Inner Transition Elements
This section deals with the characteristics of lanthanoids and actinoids, focusing on their unique orbital filling and properties.

### Applications of d- and f-Block Elements
The chapter also discusses the industrial significance and applications of transition metals, noting their essential roles in various sectors.

## Core Ideas

| Idea | Explanation |
| :--- | :--- |
| Transition Metals | Metals with incomplete d subshells, classified into different series based on electron filling. |
| Inner Transition Metals | Metals filling f orbitals, including lanthanoids and actinoids, located below the main body of the periodic table. |

## Key Concepts

| Concept | Meaning |
| :--- | :--- |
| d-block Elements | Elements with d orbitals being filled progressively in groups 3-12. |
| f-block Elements | Elements with 4f and 5f orbitals filled, placed at the bottom of the periodic table. |

## Important Points for Revision
* The d-block contains transition metals which have unique properties.
* The classification of transition metals includes four series: 3d, 4d, 5d, and 6d.
* Zinc, cadmium, and mercury are exceptions as they do not have incomplete d subshells.
* The filling of d and f orbitals influences the chemical reactivity and properties of these elements.
* Transition metals often exhibit multiple oxidation states.
* f-block elements consist of lanthanoids and actinoids, defined by the filling of f orbitals.
* The general trend in the properties of transition elements can be studied through their electron configurations.
* Transition metals are significant in various industrial applications, including precious metals.

## Vocabulary and Glossary

| Word / Phrase | Meaning |
| :--- | :--- |
| Lanthanoids | Elements filling the 4f orbitals, positioned in the f-block. |
| Actinoids | Elements filling the 5f orbitals, also positioned in the f-block. |

## Practice Questions

### Short Answer Questions
1. Define transition metals.
2. What are lanthanoids?
3. Identify one key property of transition metals.
4. How are f-block elements categorized?
5. Mention an application of transition metals.

### Long Answer Questions
1. Discuss the electronic configurations of transition metals and provide examples.
2. Explain the significance of oxidation states in transition metals.
3. Describe the general properties of inner transition metals and their position in the periodic table.

## Related Concepts
* Transition Metals
* Lanthanoids
* Actinoids

## Source Attribution

| Field | Value |
| :--- | :--- |
| Source | Edzy |
| Reference Type | examSubjectBookChapter |
| Reference ID | 66def8373f8b4e9e69bda494 |
| Canonical URL | https://www.edzy.ai/cbse-class-12-chemistry-chemistry-i-the-d-and-f-block-elements |
| Markdown URL | https://www.edzy.ai/okf/chapter/cbse-class-12-chemistry-chemistry-i-the-d-and-f-block-elements.md |