Atomic Structure Formulas - Chemistry Class 11

Learn important formulas from the Atomic Structure chapter of Class 11 Chemistry with examples, variables and applications.

📐 Atomic Structure Formulas

Complete collection of formulas with explanations and examples

Bohr Radius Energy

$$E_n = -13.6/n^2 eV$$

Description: Bohr Radius Energy is a standard relation used in atomic-structure.

Example:

Apply the relation: E_n = -13.6/n^2 eV

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.
  • Exam relevance: jee-main, jee-advanced, cuet, neet

de Broglie Wavelength

$$lambda = h/(mv)$$

Description: de Broglie Wavelength is a standard relation used in atomic-structure.

Example:

Apply the relation: lambda = h/(mv)

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.
  • Exam relevance: jee-main, jee-advanced, cuet, neet

Quick Reference

Bohr Radius Energy: $E_n = -13.6/n^2 eV$
de Broglie Wavelength: $lambda = h/(mv)$

💡 Worked Examples

Step-by-step solutions using Atomic Structure formulas

Example 1: Area of Circle

Circle Area Formula
Problem:

Find the area of a circle with radius 7 cm.

Solution:
  1. Given: r = 7 cm
  2. Apply formula: A = πr²
  3. Substitute: A = π × 7²
  4. Calculate: A = π × 49 = 49π cm²
  5. Approximate: A ≈ 49 × 3.14159 ≈ 153.94 cm²
Answer:

Area = 49π cm² ≈ 153.94 cm²

🎯 Practice Problems

Try these problems to test your understanding:

Practice Problem 1

Solve the quadratic equation: x² - 7x + 12 = 0

Practice Problem 2

Find the area of a circle with diameter 14 cm.

Practice Problems

Check Your Formula Recall

Write each formula once, define every variable, then solve one direct substitution problem before moving to mixed questions.

Apply Atomic Structure

Pick two formulas from this page and create your own values for the variables. Verify units and signs before calculating.

Derivation Notes

Focus on how the formula is built, not only the final expression. Derivations help with board-exam reasoning and multi-step application questions.

  • Start from the definition or identity used in the chapter.
  • Write assumptions clearly before substituting values.
  • Track units through each step to catch calculation mistakes.

Where These Formulas Are Used

Board Exam Problems

Use these formulas for direct numerical questions, proof-based steps, and short-answer reasoning in Chemistry.

Competitive Practice

Memorize the condition of use for each formula so you can identify the right expression quickly under timed practice.

Related Formula Chapters

Atomic Structure 2 formulas Chemical Bonding 1 formulas Equilibrium 2 formulas Redox Reactions 1 formulas Some Basic Concepts Of Chemistry 3 formulas Thermodynamics 1 formulas

These Atomic Structure formulas help students revise concepts quickly and apply equations accurately in exam-style problems.

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