PERIODIC TABLE AND ELECTRON CONFIGURATION | PART 1 |CHEMISTRY CHAPTER 3 | SSLC CHEMISTRY 2025

Introduction

This tutorial provides a comprehensive guide to understanding the periodic table and electron configuration, based on the content from the video "PERIODIC TABLE AND ELECTRON CONFIGURATION | PART 1" by Gradient Academy. Whether you're preparing for your SSLC Chemistry exam or simply looking to deepen your understanding of chemistry, this guide will walk you through essential concepts and practical tips.

Step 1: Understanding the Periodic Table

• The periodic table is an organized arrangement of all known chemical elements.
• Elements are categorized by increasing atomic number, which represents the number of protons in an atom's nucleus.
• Familiarize yourself with the table's structure:
  • Rows (Periods): Indicate the number of electron shells.
  • Columns (Groups): Indicate elements with similar chemical properties.

Tips for Memorization

• Use mnemonic devices to remember groups of elements.
• Focus on key groups such as alkali metals, alkaline earth metals, halogens, and noble gases.

Step 2: Exploring Electron Configuration

• Electron configuration describes the distribution of electrons in an atom's orbitals.
• The basic order for filling orbitals is based on the Aufbau principle, which states that electrons occupy the lowest energy orbitals first.
• Common orbital notations:
  • s orbitals hold a maximum of 2 electrons.
  • p orbitals hold a maximum of 6 electrons.
  • d orbitals hold a maximum of 10 electrons.
  • f orbitals hold a maximum of 14 electrons.

Practical Steps to Determine Electron Configuration

1. Identify the atomic number of the element.
2. Fill the orbitals in the following order:
   • 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
3. Write the configuration using the notation (e.g., for Oxygen, the configuration is 1s² 2s² 2p⁴).

Common Pitfalls

• Remember that the 3d orbital is filled after 4s, which can be confusing.
• Ensure you account for all electrons based on the atomic number.

Step 3: Special Cases in Electron Configuration

• Some elements, particularly transition metals, can have variations in their electron configurations due to stability.
• Example: Chromium (Cr) has the configuration [Ar] 4s¹ 3d⁵ instead of [Ar] 4s² 3d⁴.

Tips for Handling Special Cases

• Familiarize yourself with the exceptions to the general rules.
• Practice with common elements that have special configurations.

Conclusion

Understanding the periodic table and electron configuration is fundamental in chemistry. This tutorial has outlined the key concepts and steps to help you grasp these topics effectively. As a next step, consider practicing electron configurations for various elements and exploring their properties based on their position in the periodic table. For further learning, check out the additional resources linked in the video description.