PERIODIC TABLE & PERIODIC
PROPERTIES
🎯 Ultimate Revision Notes for JEE Main & JEE Advanced
Handwritten Style • Deep Conceptual Coverage • Exceptions & Advanced Trends Included
1. Development of Periodic Table & Modern Periodic Law
• Moseley's Law (1913): Frequency of characteristic X-rays (ν) emitted by elements is related to atomic number (Z) by:
√ν = a(Z - b) (where a and b are constants)
Conclusion: Atomic number (Z) is the fundamental property of an element, NOT atomic mass!
• Modern Periodic Law: "Physical and chemical properties of elements are periodic functions of their atomic numbers."
• Structure of Modern Periodic Table:
◦ 7 Horizontal Rows: Called Periods . Number of elements in period n = 2n² (for odd n) or 2(n+1)² logic based on
orbital capacity.
◦ 18 Vertical Columns: Called Groups (IUPAC recommendation 1 to 18).
💡 Advanced Formula: Finding Period, Block & Group of Element (Z)
1. Write electronic configuration using Aufbau principle.
2. Period: Highest principal quantum number (n) in configuration.
3. Block: Orbital (s, p, d, f) which receives the last entering differentiating electron.
4. Group Number:
◦ s-block: Group = No. of valence s electrons (1 or 2)
◦ p-block: Group = 12 + No. of valence p electrons
◦ d-block: Group = (n-1)d e⁻ + ns e⁻
◦ f-block: Group = Always 3 (or Group IIIB)
2. Effective Nuclear Charge (Zeff) & Slater's Rules
Concept: The outer electron experiences an attractive force from the nucleus reduced by the repulsive forces of inner electrons
(Shielding / Screening Effect).
Zeff = Z - σ (where Z = Atomic Number, σ = Shielding Constant)
JEE Advanced Ultimate Notes | Periodic Table Page 1 of 5
, Slater's Rules for Calculating σ:
Group configuration as: (1s) (2s, 2p) (3s, 3p) (3d) (4s, 4p) (4d) (4f)...
• For electron in s or p orbital:
◦ Electrons in same group contribute 0.35 each (except 1s which is 0.30).
◦ Electrons in (n-1) shell contribute 0.85 each.
◦ Electrons in (n-2) or deeper shells contribute 1.00 each.
• For electron in d or f orbital:
◦ Electrons in same group contribute 0.35 each.
◦ All electrons in groups to the left contribute 1.00 each.
⭐ Order of Shielding Power of Orbitals: s > p > d > f
Note: Poor shielding by 3d and 4f electrons leads to important periodic anomalies (d-block contraction & Lanthanide
contraction)!
3. Atomic Radius & Trends
Atomic radius isn't sharply defined because electron cloud has no sharp boundary. Types of Radii:
cov): Half of internuclear distance between two singly bonded identical non-metallic atoms (rcov = d
1. Covalent Radius (r
/ 2).
2. Metallic Radius (r
met): Half of internuclear distance between two adjacent metal cations in metallic lattice.
3. Van der Waals Radius (r
vdw): Half of distance between nuclei of two non-bonded adjacent atoms of neighboring
molecules in solid state.
🔥 Order of Magnitude of Radii for same element:
rvdw > rmet > rcov (Van der Waals is ~40-50% larger than covalent radius!)
General Periodic Trends in Atomic Size:
• Across a Period (L → R ): Z
eff increases → Size decreases.
• Down a Group (Top → Bottom): Principal shell n increases → Size increases.
🚨 CRITICAL EXCEPTIONS & JEE ADVANCED SPECIAL TRAPS:
1. Group 13 Size Anomaly: B < Al ≈ Ga < In < Tl
◦ Why Ga ≤ Al? Transition State Contraction (d-block contraction). Ga has 10 3d electrons which screen nucleus
poorly, so Zeff increases sharply.
2. 4d vs 5d Series (Lanthanide Contraction):
◦ Size order: 3d < 4d ≈ 5d
JEE Advanced Ultimate Notes | Periodic Table Page 2 of 5
PROPERTIES
🎯 Ultimate Revision Notes for JEE Main & JEE Advanced
Handwritten Style • Deep Conceptual Coverage • Exceptions & Advanced Trends Included
1. Development of Periodic Table & Modern Periodic Law
• Moseley's Law (1913): Frequency of characteristic X-rays (ν) emitted by elements is related to atomic number (Z) by:
√ν = a(Z - b) (where a and b are constants)
Conclusion: Atomic number (Z) is the fundamental property of an element, NOT atomic mass!
• Modern Periodic Law: "Physical and chemical properties of elements are periodic functions of their atomic numbers."
• Structure of Modern Periodic Table:
◦ 7 Horizontal Rows: Called Periods . Number of elements in period n = 2n² (for odd n) or 2(n+1)² logic based on
orbital capacity.
◦ 18 Vertical Columns: Called Groups (IUPAC recommendation 1 to 18).
💡 Advanced Formula: Finding Period, Block & Group of Element (Z)
1. Write electronic configuration using Aufbau principle.
2. Period: Highest principal quantum number (n) in configuration.
3. Block: Orbital (s, p, d, f) which receives the last entering differentiating electron.
4. Group Number:
◦ s-block: Group = No. of valence s electrons (1 or 2)
◦ p-block: Group = 12 + No. of valence p electrons
◦ d-block: Group = (n-1)d e⁻ + ns e⁻
◦ f-block: Group = Always 3 (or Group IIIB)
2. Effective Nuclear Charge (Zeff) & Slater's Rules
Concept: The outer electron experiences an attractive force from the nucleus reduced by the repulsive forces of inner electrons
(Shielding / Screening Effect).
Zeff = Z - σ (where Z = Atomic Number, σ = Shielding Constant)
JEE Advanced Ultimate Notes | Periodic Table Page 1 of 5
, Slater's Rules for Calculating σ:
Group configuration as: (1s) (2s, 2p) (3s, 3p) (3d) (4s, 4p) (4d) (4f)...
• For electron in s or p orbital:
◦ Electrons in same group contribute 0.35 each (except 1s which is 0.30).
◦ Electrons in (n-1) shell contribute 0.85 each.
◦ Electrons in (n-2) or deeper shells contribute 1.00 each.
• For electron in d or f orbital:
◦ Electrons in same group contribute 0.35 each.
◦ All electrons in groups to the left contribute 1.00 each.
⭐ Order of Shielding Power of Orbitals: s > p > d > f
Note: Poor shielding by 3d and 4f electrons leads to important periodic anomalies (d-block contraction & Lanthanide
contraction)!
3. Atomic Radius & Trends
Atomic radius isn't sharply defined because electron cloud has no sharp boundary. Types of Radii:
cov): Half of internuclear distance between two singly bonded identical non-metallic atoms (rcov = d
1. Covalent Radius (r
/ 2).
2. Metallic Radius (r
met): Half of internuclear distance between two adjacent metal cations in metallic lattice.
3. Van der Waals Radius (r
vdw): Half of distance between nuclei of two non-bonded adjacent atoms of neighboring
molecules in solid state.
🔥 Order of Magnitude of Radii for same element:
rvdw > rmet > rcov (Van der Waals is ~40-50% larger than covalent radius!)
General Periodic Trends in Atomic Size:
• Across a Period (L → R ): Z
eff increases → Size decreases.
• Down a Group (Top → Bottom): Principal shell n increases → Size increases.
🚨 CRITICAL EXCEPTIONS & JEE ADVANCED SPECIAL TRAPS:
1. Group 13 Size Anomaly: B < Al ≈ Ga < In < Tl
◦ Why Ga ≤ Al? Transition State Contraction (d-block contraction). Ga has 10 3d electrons which screen nucleus
poorly, so Zeff increases sharply.
2. 4d vs 5d Series (Lanthanide Contraction):
◦ Size order: 3d < 4d ≈ 5d
JEE Advanced Ultimate Notes | Periodic Table Page 2 of 5
