Practice Questions →

Chapter 2: Structure of Atom

NCERT Solutions for CBSE Class 10 Chemistry — 52 solved questions with detailed explanations.

52

Questions

0

Topics

Solved Questions

Q1. The de Broglie wavelength of an electron moving with velocity v is:

h/mv
hv/m
mh/v
mv/h

Difficulty: Easy · Topic: de Broglie

Solution

λ = h/p = h/(mv), where h is Planck's constant.

Q2. Maximum electrons in shell n=1:

Difficulty: Easy · Topic: Quantum

Solution

Max = 2n² = 2*1² = 2.

Q3. Maximum electrons in shell n=2:

Difficulty: Easy · Topic: Quantum

Solution

Max = 2n² = 2*2² = 8.

Q4. Maximum electrons in shell n=3:

Difficulty: Easy · Topic: Quantum

Solution

Max = 2n² = 2*3² = 18.

Q5. Maximum electrons in shell n=4:

Difficulty: Easy · Topic: Quantum

Solution

Max = 2n² = 2*4² = 32.

Q6. Maximum electrons in shell n=5:

Difficulty: Easy · Topic: Quantum

Solution

Max = 2n² = 2*5² = 50.

Q7. Maximum electrons in shell n=6:

Difficulty: Easy · Topic: Quantum

Solution

Max = 2n² = 2*6² = 72.

Q8. Maximum electrons in shell n=7:

Difficulty: Easy · Topic: Quantum

Solution

Max = 2n² = 2*7² = 98.

Q9. Max electrons in 1s subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*1=2.

Q10. Max electrons in 2s subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*1=2.

Q11. Max electrons in 2p subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*3=6.

Q12. Max electrons in 3s subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*1=2.

Q13. Max electrons in 3p subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*3=6.

Q14. Max electrons in 3d subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*5=10.

Q15. Max electrons in 4s subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*1=2.

Q16. Max electrons in 4p subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*3=6.

Q17. Max electrons in 4d subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*5=10.

Q18. Max electrons in 4f subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*7=14.

Q19. Max electrons in 5s subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*1=2.

Q20. Max electrons in 5p subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*3=6.

Q21. Max electrons in 5d subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*5=10.

Q22. Max electrons in 5f subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*7=14.

Q23. Max electrons in 5g subshell:

Difficulty: Easy · Topic: Quantum

Solution

2(2l+1)=2*9=18.

Q24. The maximum number of electrons in a subshell with l = 2 is:

6
10
14
2

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(5) = 10. l=2 is d subshell.

Q25. The electronic configuration of Fe (Z=26) is:

[Ar]3d⁶ 4s²
[Ar]3d⁸
[Ar]3d⁵ 4s² 4p¹
[Ar]3d⁴ 4s² 4p²

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Fe: [Ar] 3d⁶ 4s². The 4s fills before 3d (Aufbau principle).

Q26. Heisenberg's uncertainty principle states that:

Δx · Δp ≥ h/4π
Δx · Δp ≥ h/2π
Δx · Δp ≥ h
Δx · Δv ≥ h/4π

Difficulty: Easy-Medium · Topic: Uncertainty Principle

Solution

Δx · Δp ≥ h/(4π) = ħ/2. This sets a fundamental limit on simultaneous measurement of position and momentum.

Q27. The electronic configuration of Na (Z=11) is:

[Ar]3s¹
[Ne]2s¹
[Ne]3p¹
[Ne]3s¹

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: Na (Z=11) has config [Ne]3s¹.

Q28. The electronic configuration of Cl (Z=17) is:

[Ar]3s²3p⁵
[Ne]3s²3p⁵
[Ne]3s²3p⁶
[Ne]3s²3p³

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: Cl (Z=17) has config [Ne]3s²3p⁵.

Q29. The electronic configuration of Ca (Z=20) is:

[Ne]4s²
[Ar]4s²
[Ar]4p²
[Ar]3d²

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: Ca (Z=20) has config [Ar]4s².

Q30. The electronic configuration of Cu (Z=29) is:

[Ar]3d¹⁰4s²
[Ar]3d⁹ 4s²
[Ar]3d⁸ 4s¹
[Ar]3d¹⁰4s¹

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: Cu (Z=29) has config [Ar]3d¹⁰4s¹.

Q31. The electronic configuration of Cr (Z=24) is:

[Ar]3d⁴5s¹
[Ar]3d⁴ 4s²
[Ar]3d⁶
[Ar]3d³ 4s² 4p¹

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: Cr (Z=24) has config [Ar]3d⁴5s¹.

Q32. The electronic configuration of K (Z=19) is:

[Ne]4s¹
[Ar]4s¹
[Ar]4p¹
[Ar]3d¹

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: K (Z=19) has config [Ar]4s¹.

Q33. The electronic configuration of Sc (Z=21) is:

[Ar]3d³
[Ar]4s²4p¹
[Ar]3d¹4s²
[Ar]3d²4s¹

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: Sc (Z=21) has config [Ar]3d¹4s².

Q34. The electronic configuration of Ni (Z=28) is:

[Ar]3d⁹4s¹
[Ar]3d⁸4s²
[Ar]3d⁶ 4s²4p²
[Ar]3d¹⁰4s⁻²

Difficulty: Easy-Medium · Topic: Electronic Configuration

Solution

Following Aufbau, Hund's, and Pauli's rules: Ni (Z=28) has config [Ar]3d⁸4s².

Q35. The maximum number of electrons in 1s subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(1) = 2.

Q36. The maximum number of electrons in 2s subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(1) = 2.

Q37. The maximum number of electrons in 2p subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(3) = 6.

Q38. The maximum number of electrons in 3s subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(1) = 2.

Q39. The maximum number of electrons in 3p subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(3) = 6.

Q40. The maximum number of electrons in 3d subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(5) = 10.

Q41. The maximum number of electrons in 4s subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(1) = 2.

Q42. The maximum number of electrons in 4p subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(3) = 6.

Q43. The maximum number of electrons in 4d subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(5) = 10.

Q44. The maximum number of electrons in 4f subshell is:

Difficulty: Easy-Medium · Topic: Quantum Numbers

Solution

Max electrons = 2(2l+1) = 2(7) = 14.

Q45. Electronic configuration of Na⁺ (Z=11):

[He]2s²
[Ar]
[Ne]3s¹
[Ne] = 1s²2s²2p⁶

Difficulty: Medium · Topic: Ion Configuration

Solution

Na⁺ (Z=11) has configuration [Ne] = 1s²2s²2p⁶.

Q46. Electronic configuration of Cl⁻ (Z=17):

[Ne]3s²3p⁵
[Ar]3s²
[Ne]3s²
[Ar] = [Ne]3s²3p⁶

Difficulty: Medium · Topic: Ion Configuration

Solution

Cl⁻ (Z=17) has configuration [Ar] = [Ne]3s²3p⁶.

Q47. Electronic configuration of Fe²⁺ (Z=26):

[Ar]3d⁵ 4s¹
[Ar]3d⁶
[Ar]3d⁶ 4s²
[Ar]3d⁴ 4s²

Difficulty: Medium · Topic: Ion Configuration

Solution

Fe²⁺ (Z=26) has configuration [Ar]3d⁶.

Q48. Electronic configuration of Fe³⁺ (Z=26):

[Ar]3d⁴ 4s²
[Ar]3d⁶
[Ar]3d³ 4s²
[Ar]3d⁵

Difficulty: Medium · Topic: Ion Configuration

Solution

Fe³⁺ (Z=26) has configuration [Ar]3d⁵.

Q49. Electronic configuration of Cu⁺ (Z=29):

[Ar]3d¹⁰
[Ar]3d⁹ 4s¹
[Ar]3d⁸ 4s²
[Ar]3d¹⁰ 4s¹

Difficulty: Medium · Topic: Ion Configuration

Solution

Cu⁺ (Z=29) has configuration [Ar]3d¹⁰.

Q50. Electronic configuration of Cu²⁺ (Z=29):

[Ar]3d⁸ 4s¹
[Ar]3d¹⁰
[Ar]3d⁹
[Ar]3d⁷ 4s²

Difficulty: Medium · Topic: Ion Configuration

Solution

Cu²⁺ (Z=29) has configuration [Ar]3d⁹.

Q51. Electronic configuration of Zn²⁺ (Z=30):

[Ar]3d⁹
[Ar]3d⁸ 4s²
[Ar]3d¹⁰
[Ar]3d¹⁰ 4s²

Difficulty: Medium · Topic: Ion Configuration

Solution

Zn²⁺ (Z=30) has configuration [Ar]3d¹⁰.

Q52. Electronic configuration of Mg²⁺ (Z=12):

[Ne]3s¹
[Ne] = 1s²2s²2p⁶
[He]2s²
[Ne]3s²

Difficulty: Medium · Topic: Ion Configuration

Solution

Mg²⁺ (Z=12) has configuration [Ne] = 1s²2s²2p⁶.

Other Chapters in Chemistry

Ch 1: Some Basic Concepts Ch 3: Classification of Elements Ch 4: Chemical Bonding Ch 5: States of Matter Ch 6: Thermodynamics Ch 7: Equilibrium Ch 8: Redox Reactions Ch 9: Hydrogen Ch 10: s-Block Elements Ch 11: p-Block Elements Ch 12: Organic Chemistry Ch 13: Hydrocarbons Ch 14: Environmental Chemistry

Want to practice these questions interactively?

Get instant feedback, track progress, and improve with adaptive practice.

Start Practicing Free →