(LONG NOTES) Chemical Bonding NEET 2025 - UrEducator

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INSIGHTS

⚡ NEET 2025 CHEMICAL BONDING ⚡

💎 3 GOLDEN FACTS (NEET 2015-24)

78%

Questions from VSEPR/Hybridization

4x

More bond order questions than lattice enthalpy

0

Direct Fajan's rule questions since 2020

⚖️ IONIC vs COVALENT BONDS

Feature	Ionic Bond	Covalent Bond	NEET Frequency
Formation	Electron transfer	Electron sharing	2 Q/yr
Electronegativity Difference	>1.7	<1.7	1 Q/yr
Examples	NaCl, CaF2	H2, CH4	3 Q/yr

⚛️ Kossel-Lewis Approach (1916)

Key Concepts:

• Octet Rule: Atoms gain/lose/share electrons to achieve 8 valence electrons
• Ionic Bond: Complete electron transfer (Na⁺Cl^-)
• Covalent Bond: Electron sharing (H:H)
• Lattice Enthalpy: Energy released when 1 mole of ionic solid forms from gaseous ions

📜 Fajan's Rule (Polarization Power)

Covalent character increases when:

• Cation is small and highly charged (Al³⁺)
• Anion is large (I^-)
• Cation has pseudo-noble gas configuration (Cu⁺)

Example:
LiI > LiF in covalent character

NEET Trick:
"Small cation + Big anion = More covalent"

🎯 PYQ Highlights:

NEET 2021: Highest lattice energy among NaCl, MgCl₂, AlCl₃? Answer: AlCl₃ (higher charge)

NEET 2019: Which shows maximum covalent character? Answer: AlI₃ (Fajan's rule)

🧠 DIPOLE MOMENT MNEMONIC

"CO₂ Zero, H₂O High"

CO₂ (μ=0) - Symmetrical linear
H₂O (μ=1.85D) - Bent structure

NEET Hack: "More electronegativity difference → Higher dipole moment"

🔵 VSEPR Theory (Gillespie-Nyholm)

Key Principles:

• Electron pairs repel to maximize distance
• Lone pairs repel more than bond pairs
• Order of repulsion: LP-LP > LP-BP > BP-BP

Common Shapes:

• AX₂: Linear (180°), e.g., BeCl₂
• AX₃: Trigonal planar (120°), e.g., BF₃
• AX₄: Tetrahedral (109.5°), e.g., CH₄
• AX₅: Trigonal bipyramidal, e.g., PCl₅
• AX₆: Octahedral (90°), e.g., SF₆

🎯 PYQ Highlights:

NEET 2022: Shape of XeF₄? Answer: Square planar

NEET 2020: Bond angle in H₂O vs CH₄? Answer: 104.5° < 109.5° (lone pair effect)

Formula	Shape	Angle	Example
AX2E	Bent	~120°	SO2
AX2E2	Bent	~104.5°	H2O

🌀 Hybridization (Linus Pauling)

Key Concepts:

• Mixing of atomic orbitals to form new hybrid orbitals
• sp³: Tetrahedral (4 σ bonds), e.g., CH₄
• sp²: Trigonal planar (3 σ + 1 π), e.g., C₂H₄
• sp: Linear (2 σ + 2 π), e.g., C₂H₂
• dsp³: Trigonal bipyramidal, e.g., PCl₅
• d²sp³: Octahedral, e.g., SF₆

Hybridization Identification:

Formula: H = ½(V + M - C + A)

Where:
V = Valence electrons of central atom
M = Monovalent atoms attached
C = Cation charge
A = Anion charge

H=2: sp (Linear)
e.g., BeCl₂

H=3: sp²
e.g., BF₃

H=4: sp³
e.g., CH₄

🎯 PYQ Highlights:

NEET 2021: Hybridization in XeF₄? Answer: sp³d²

NEET 2019: Hybridization of C in HCN? Answer: sp

🌌 Molecular Orbital Theory

Key Concepts:

• LCAO: Linear Combination of Atomic Orbitals
• Bonding (σ): Lower energy, constructive interference
• Antibonding (σ*): Higher energy, destructive interference
• Bond Order = ½(N_b - N_a)

Homonuclear Diatomics:

Order of filling: σ1s < σ*1s < σ2s < σ*2s < σ2p_z < π2p_x=π2p_y < π*2p_x=π*2p_y < σ*2p_z

O₂: Paramagnetic (2 unpaired electrons in π* orbitals)

🎯 PYQ Highlights:

NEET 2020: Bond order of O₂⁺? Answer: 2.5

NEET 2018: Which is paramagnetic? Answer: B₂

σ*2p_z

π*2p_x,y

↑↑

σ2p_z

π2p_x,y

O₂ Molecular Orbital Diagram

📈 NEET 2025 Predictions

High Probability Topics:

• Hybridization and shapes (especially sp³d and sp³d²)
• Bond order calculations (O₂, N₂, their ions)
• VSEPR theory applications (Xe compounds)

Dark Horse Candidates:

• Hydrogen bonding in biological molecules
• Back bonding (BF₃, CO)
• Metallic bonding (electron sea model)

🧠 Mnemonics & Quick Recall

"VSEPR Shapes":
2 - Linear
3 - Trigonal
4 - Tetra
5 - Bipyramidal
6 - Octa

"Hybridization":
sp - 180°
sp² - 120°
sp³ - 109.5°
dsp³ - 90°,120°

💡 NEET 2025 Master Strategy

• ✅ Practice 50+ hybridization problems (focus on exceptions)
• ✅ Memorize all VSEPR shapes (make flashcards for AX_nE_m types)
• ✅ Solve all PYQs from 2015-2024 (especially MO diagrams)

With these strategies, you'll master Chemical Bonding for NEET 2025! ⚛️🚀

🚨 NEET BONDING ALERT!

VSEPR Theory asked every year since 2015 - Master it now!

Download Bonding Notes (PDF) PYQs With Solutions More NEET Topics

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