P-Block Elements Notes for NEET – Complete Chapter

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INTRODUCTION & INERT PAIR EFFECT

P-Block Basics

Last e⁻ enters p-subshell (orbital).

Total groups in p-block = 6 (13th to 18th) — because max 6 e⁻ can be in p-subshell.

Group Oxidation State (Higher O.S.): nse⁻ + npe⁻ → e.g. ns²np³: Group O.S. = 2+3 = 5

Inert Pair Effect

Definition

The tendency of ns e⁻ pair to get inert while coming down the group is called inert pair effect.

Reason: Due to involvement of d and f e⁻ in lower members of p-block → nucleus is heavy → shielding is poor → attraction on ns e⁻ pair ↑ due to d & f e⁻.

Poor shielding: (n-2)f¹⁴ (n-1)d¹⁰

Consequences of Inert Pair Effect

On moving down the group → stability of lower O.S. ↑ (H.O.S. ↓se)
Higher O.S. → ns e⁻ + np e⁻
Lower O.S. → Higher O.S. − 2 unit (due to inertness of 2ns e⁻)
O.S. two unit less than group O.S. becomes progressively more stable while moving down the group

Stability of O.S. — Group wise

Group	Higher O.S. (H.O.S.)	Lower O.S. (L.O.S.)	Stability Trend
13th (ns²np¹)	+3 → B³⁺>Al³⁺>Ga³⁺>In³⁺>Tl³⁺	+1 → B⁺¹<Al⁺¹<Ga⁺¹<In⁺¹<Tl⁺¹	Most stable O.S. = +3
14th (ns²np²)	+4 → C⁴⁺>Si⁴⁺>Ge⁴⁺>Sn⁴⁺>Pb⁴⁺	+2 → C²⁺<Si²⁺<Ge²⁺<Sn²⁺<Pb²⁺	Most stable O.S. = +2 (Pb)
15th (ns²np³)	+5 → N⁵⁺>P⁵⁺>As⁵⁺>Sb⁵⁺>Bi⁵⁺	+3 → N³⁺<P³⁺<As³⁺<Sb³⁺<Bi³⁺	Bi³⁺ most stable
16th (ns²np⁴)	+6 → S⁺⁶ most stable	+4, +2 → Te most stable	Most stable O.S. of Te = +2,+4,+6

Important — Oxidizing Agents (Inert Pair)

Cu²⁺, Bi⁺⁵, Pb⁴⁺, Fe³⁺ → Oxidizing agents (accept e⁻, get reduced to stable lower O.S.)
Fluorine can stabilize compound in higher O.S. due to its high oxidizing nature and high E.N.

Q: Which element can't form compound in +5 O.S. with halogens?

✅ Ans: (a) N — NX₅ not exist (N can't form 5 bonds — no vacant d orbital)

Q: Which two elements in +3 O.S. will be least stable towards disproportionation rxn?

✅ Ans: (b) N, P — N³⁺<P³⁺<As³⁺<Sb³⁺<Bi³⁺ (least stable in L.O.S. = most reactive)

Q: PbI₄ does not exist — True or False?

✅ Ans: True — Pb⁴⁺ (O.A.) would oxidize I⁻ (R.A.) → PbI₂ forms instead. Pb: [Xe] 4f¹⁴5d¹⁰6s²6p² — 6s² pair stays inert.

🟢

GROUP 13 — BORON FAMILY

Boron (B)

Rare element
Occurs as H₃BO₃, Borax (Na₂B₄O₇·10H₂O), Kernite (Na₂B₄O₇·7H₂O)
Two isotopes: ¹⁰B (19%), ¹¹B (81%)

Aluminium (Al)

Most abundant metal
3rd most abundant element (O₂>Si>Al)
Main ore: Bauxite (Al₂O₃·xH₂O) & Cryolite (Na₃AlF₆)

Nihonium (Nh) — Z=113

Radioactive. Half life = 20 sec.

Atomic Properties of Group 13

Property	Trend / Order	Reason
Size	B < Al > Ga < In < Tl	Ga anomaly due to transition contraction (poor shielding of 3d e⁻)
Ionisation Energy	B > Al < Ga > In < Tl	Transition + Lanthanoid contraction
Final IE Order	B > Tl > Ga > Al > In	—
Electronegativity	B=2.0, Al=1.5, Ga=1.6, In=1.7, Tl=1.8	Largest gap b/w B & Al
Density	Increase top to bottom	—
Boiling Pt	Decrease top to bottom	—
Melting Pt	B>Al>(Ga min)<In<Tl \| Final: B>Al>Tl>In>Ga	Ga used to measure temp (Low MP 303K, High BP 2600K)

Chemical Reactivity of Group 13

Reactivity with Air (O₂+N₂)

Crystalline B → Non reactive
Crystalline Al → Protective oxide layer (very less reactive)
Amorphous B & Al can react with air
E + O₂ → E₂O₃ (e.g. B₂O₃, Al₂O₃)
E + N₂ → EN (e.g. BN, AlN)

Oxide of B → Acidic | Al, Ga → Amphoteric | In, Tl → Basic

Reactivity with Halogens

E + X₂ → EX₃ (Trihalide) — Covalent
Note: TlI₃ not exist (Tl³⁺ 3I⁻ not exist) due to inert pair effect
Tl is stable in +1 O.S.

EX₃ → 6e⁻ (e⁻ deficient), incomplete octet, Lewis acid

Reactivity with Acid & Base (Al — Amphoteric)

B + Acid/Base → No rxn

Al + Acid/Base → reaction occurs, H₂ gas evolves

Al + HCl → AlCl₃ + H₂↑ | Al + Conc. HNO₃ → Passivation (surface becomes inert)

Al + NaOH(aq) → Na[Al(OH)₄] + H₂↑ [Sodium tetrahydroxidoaluminate(III)]

⭐ This rxn is used to remove blockage from drainage pipe!

Conc. HNO₃ also reacts with: Be, Al, Fe, Cr (Passivation)

AlCl₃ Dimerisation → Al₂Cl₆

AlCl₃ has 6e⁻ (e⁻ deficient) → forms dimer Al₂Cl₆ to complete octet (8e⁻)

Features: Bridge bond (2), Halogen bridged dimer

BCl₃ CANNOT form dimer — B₂Cl₆ can't form because large size of Cl can't fit into voids b/w B atoms.

Lewis Acid Strength Order

BF₃ < BCl₃ < BBr₃ < BI₃ (Lewis acid nature ↑)

Donation strength ↓ → Extent of B.B ↑ → Lewis acid nature ↑

Also: BCl₃ > AlCl₃ > GaCl₃ > InCl₃ [size of cation ↑ → LP accepting tendency ↓ → not based on B.B]

🧪

BORAX, BORIC ACID & BACK BONDING

Borax [Na₂B₄O₇·10H₂O]

Key Facts

Both sp² & sp³ Boron are present
Trigonal planar & tetrahedral units are present
Borax bead test is used to identify transition metals
Real formula: [Na₂B₄O₅(OH)₄·8H₂O]
5 B−O−B linkages, 5 bridging oxygens
Borax + H₂O → Alkaline solution

Orthoboric Acid [H₃BO₃]

Trigonal planar unit (BO₃)³⁻
In solid: polymeric due to presence of H-Bonding
Weak acid (Lewis acid), Monobasic
Not a protonic acid (Apne H⁺ नहीं देता)
B(OH)₃ + H₂O → B(OH)₄⁻ + H⁺ (released from water)

Back Bonding in Boron Trihalide

Back Bonding — Definition

π co-ordinate bond b/w two adjacent covalently bonded atom. It is a special case of resonance.

Condition of BB:

One atom must be from 2nd period because π-bond is distance sensitive
One atom should have L.P. and other should have vacant orbital

Effect of Back Bonding (Always in BF₃)

B.O. ↑ se
B.L. ↓ se
B.S. ↑ se

In BF₃: B−F bond order ↑ & B.L. ↓ se due to BB

Note: If L.P. of central atom participates in B.B. then hybridization, geometry, bond angle may also change. e.g. H₃Si−NH₂ (Si has vacant d') → sp² hybridised N, trigonal planar, 120°

Special Cases — When Back Bonding can/can't occur

BF₃ ✓ (vacant orbital, 2nd period)
NH₃·BF₂ ✓ (vacant orbital present after reaction)
AlCl₃ ✗ (3rd−3rd period — not 2nd period)
SiCl₄ ✗ (3rd−3rd period)
NH₃·BF₃ ✗ (no vacant orbital after adduct formation)
NH₃ ✗ (no vacant orbital)

NNH₂ > NH₂−BF₂ (Lewis Base) — NNH₂: No BB, LP free | NH₂BF₂: BB, LP busy

In H₃BO₃: LP of oxygen busy in BB | In H₃BO₃: Hybridization of B → sp² due to BB

Q: In which of following special BB can be tnt: (i) BF·F (ii) BF₃ (iii) AlCl₃ (iv) SiCl₄ (v) NH₃·BF₃ (vi) NH₂−BF₂ (vii) NH₃

✅ Ans: Only (ii) BF₃ and (vi) NH₂−BF₂ show Back Bonding

🔵

DIBORANE [B₂H₆]

Key Properties

Dimer of BH₃
Used as rocket fuel
Two bridging 'H' atoms
B is sp³ hybridised
Two bridging H's and two B's are in same plane

Structure Facts

Colourless toxic gas
Psychophoric (catches fire)
Four terminal 'H' atoms
Two bridging bond (3 centre 2e⁻ — banana bond) → e⁻ deficient
Max 6 atoms in same plane

Bond Orders

B−H (terminal) B.O. = 1 | B−H (bridging) B.O. = 0.5 → B.O. < B.L ↑

Species	e⁻ deficient?	Reason
AlCl₃ ✗	No	Ionic: octet complete
AlCl₂ ✓	Yes	—
AlF₃ ✗	No	Ionic: octet complete
BH₃ ✓	Yes	6e⁻ only
B₂H₆ ✓	Yes	Banana bond
NH₃ ✗	No	e⁻ rich
CCl₄ ✗	No	e⁻ precise

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GROUP 14 — CARBON FAMILY

Elements

C [Carbon] | Si [Silicon] | Ge [Germanium] | Sn [Tin] | Pb [Lead]

Carbon isotopes: ¹²C, ¹³C (naturally), ¹⁴C (radioactive — Half life 5770 yr — used in Carbon dating)

Atomic Properties

Property	Order
Size	C < Si < Ge < Sn < Pb
Ionisation Energy	C > Si > Ge > (Pb) > Sn (Lanthanoid contraction)
Electronegativity	C=2.5, Si=1.8, Ge=1.8, Sn=1.8, Pb=1.9
Density	C(graphite) < Si < Ge < Sn < Pb \| Diamond: C>Si
Boiling Point	from Si to Pb ↓
Melting Point	same as order of Ionisation Energy

Chemical Properties of Group 14

Reactivity with O₂

E + O₂ → MO/MO₂

CO (neutral), CO₂, SiO, SiO₂, PbO, PbO₂, GeO, GeO₂, SnO, SnO₂

Oxide of C, Si, Ge → Acidic | Oxide of Sn, Pb → Amphoteric

Reactivity with H₂O

C/Si/Ge/Sn/Pb + H₂O(l) → No rxn

Sn + Steam [H₂O(g)] → SnO₂ + H₂↑

Pb was expected to react but remains unreactive due to presence of protective oxide layer.

Reactivity with Halogens

E + X₂ → EX₂/EX₄ (Dihalide/Tetrahalide)

Stability of EX₂ ↑ down the group | Stability of EX₄ ↓ down (inert pair effect)

EX₄ are more covalent than EX₂ | Except PbF₄ & SnF₄ — all are covalent

PbI₄ doesn't exist.

Catenation Order

C >> Si > Ge ≅ Sn → Lead doesn't show catenation

💎

ALLOTROPES OF CARBON

Property	Diamond	Graphite	Fullerene (C₆₀)
Hybridisation	sp³	sp²	sp²
Structure	3D network, each C linked with 4C tetrahedrally	Layered, hexagonal rings, weak VdW b/w layers	Aromatic & synthetic, both pentagon & hexagon
Hardness	Hardest substance in nature (Abnormally high M.P.)	Softer than Diamond (lubricant)	Synthetic & purest allotrope (no dangling bond)
Electrical	Insulator (delocalized e⁻ absent)	Conductor (π e⁻ present)	—
Thermal	Conductor (strong bonds)	Less than Diamond	—
Stability	—	Thermodynamically most stable allotrope of C	—
Volume	—	More than Diamond	—

Fullerene Extra Points

Graphite → (electric arc, He/Ar) → Vapour Cⁿ → (condensation) → Black sooty powder (mainly C₆₀)

Both pentagon & hexagon are present (hexagon more always)

Allotropes of Phosphorus

White Phosphorus (P₄)

Exists as discrete units
Weak VdW b/w units
6 P−P linkages
Discrete tetrahedral

Red Phosphorus (P₄)ₙ

Polymerised
Iron grey in colour
Less reactive

Black Phosphorus

Graphite like structure. Thermodynamically most stable allotrope of P. α-Black & β-Black P present.

Allotropes of Sulphur

S₈ (Main allotrope)

Crown shaped
sp³ hybridised 'S'
α-S₈ → yellow, orthorhombic
β-S₈ → colourless, monoclinic

Other Forms

S₂: exists at high temp (~1000K), 2 unpaired e⁻ in π ABMO
S₆: chair form

📊

GROUP 15 TO 18 — ATOMIC PROPERTIES

Property	Gp 15	Gp 16	Gp 17	Gp 18
Size (↑ top→bottom)	N<P<As<Sb<Bi	O<S<Se<Te	F<Cl<Br<I	He<Ne<Ar<Kr<Xe
IE (↓ top→bottom)	Decreases	Decreases	Decreases	Decreases
Electron Affinity (Gp 16)	—	S>Se>Te>Po>O	Cl>F>Br>I	—
Density	Increases top to bottom (Gp 15 to 18)
Boiling Point	Increases top to bottom (exception: Te>Po, Sb>Bi)
Melting Point Gp 15	As>Sb>Bi>P>N	Te>Po>Se>S>O	Increases ↑	Increases ↑

Oxidation States

Gp 13: Stability of +1 ↑se, +2 ↓se | Boron can't exist as B³⁺ ion (can exist in +3 O.S.) due to High sum of IE₁, IE₂, IE₃ | Al exists as Al³⁺
Gp 14: Stability of +2 ↑se, +4 ↓se
Gp 15: Common O.S. = −3, +3, +5 | Except N, all show allotropy | Only Bi(V) compound is BiF₅
Gp 16: Read NCERT for oxidation states
Gp 17: F&Cl are gases, Br is liquid, I is solid at room temp

⚗️

CHEMICAL REACTIVITY (GROUPS 15–17)

Reactivity with O₂

Group	Products	Nature of Oxide
Gp 15	E₂O₃ (+3) / E₂O₅ (+5) \| NO & N₂O — Neutral	N & P: Acidic \| As & Sb: Amphoteric \| Bi: Basic
Gp 16	EO₂ (+4) / EO₃ (+6) — all Acidic \| SO₂ = R.A. \| TeO₂ = O.A.	All Acidic
Gp 17	Mostly unstable oxides	—
F + O₂	OF₂/O₂F₂ (fluorides of O) ∵ EN(F)>EN(O)	Fluorinating agent
Cl + O₂	Cl₂O/ClO₂/Cl₂O₆/Cl₂O₇ — all O.A. & explosive	Acidic
Br + O₂	Br₂O/BrO₂/Br₂O₃ — very less stable	—
I + O₂	I₂O₄/I₂O₅/I₂O₇ — colourful solids, O.A. \| I₂O₅ used in estimation of CO in automobiles	—

Stability of Halogen Oxides

I > Cl > Br — I has extra strength because 2 reasons, Cl has ability to form multiple bonds O=Cl, Br lacks both.

Reactivity with Halogens

Gp 15: E + X₂ → EX₃/EX₅ | EX₃ < EX₅ (covalent character) | EX₅ of Nitrogen doesn't exist | Except BiF₃ all EX₃ are covalent

Gp 16: E + X₂ → EX₂/EX₄/EX₆ (gaseous) | Only hexafluoride exists because of small size of F | Cl, Br, I hexafluoride unstable due to steric hindrance

SF₄: sp³d, see-saw (for all EX₄) | E₂X₂ (dimer): S₂F₂, S₂Cl₂, S₂Br₂, Se₂Cl₂, Se₂Br₂ (X = Cl/Br mainly)

Gp 17 (Interhalogen): X₂ + X'₂ → XX'/XX'₃/XX'₅/XX'₇ | e.g. ClF, BrF₃, BrF₅, ClF₅, IF₇

Intermolecular attraction more in interhalogen | Interhalogens have polar bond, normal halogens have non-polar bond

M.Pt & B.Pt of interhalogen > halogen

Halogen Reactivity with Water

F₂ + H₂O → HF + O₂↑ (F₂ is strongest O.A. due to high hydration enthalpy of F⁻)

Cl₂ + H₂O → HCl + HOCl (bleaching agent)

Br₂ + H₂O → HBr + HOBr

I₂ + H₂O → Non-spontaneous rxn

Oxidising power: F₂ > Cl₂ > Br₂ > I₂ | Halides (Reducing agent): F⁻ < Cl⁻ < Br⁻ < I⁻

F−F bond energy is very less (more reactive) due to L.P.−L.P. repulsion

Reactivity Order

F₂ → LP-LP repulsion | Interhalogen | Normal Halogen Cl₂/Br₂/I₂

Chlorine — Important

Chlorine is strong bleaching agent (due to oxidation) by NOCl

Interhalogen compounds are very useful fluorinating agents

ClF₃ & BrF₃ are used for production of UF₆ in enrichment of ²³⁵U:

U(s) + 3ClF₃(l) → UF₆(g) + 3ClF(g)

💧

HYDRIDES OF GROUPS 15, 16, 17

Hydride Formation

All hydrides → Covalent, Lewis Basic, e⁻ rich hydride

Gp 15: EH₃ (NH₃, PH₃, AsH₃, SbH₃) | Gp 16: H₂E (H₂O, H₂S, H₂Se, H₂Te) | Gp 17: HE (HF, HCl, HBr, HI)

Boiling Point & Melting Point

MDJ Trick — B.Pt order

Groups 15, 16, 17 — Anomaly due to H-bonding in NH₃, H₂O, HF

B.Pt: NH₃ → rank 2 | H₂O → rank 1 | HF → rank 1

Gp 15 B.Pt rank	Gp 16 B.Pt rank	Gp 17 B.Pt rank
NH₃ = 2	H₂O = 1	HF = 1
PH₃ = 4	H₂S = 4	HCl = 4
AsH₃ = 3	H₂Se = 3	HBr = 3
SbH₃ = 1	H₂Te = 2	HI = 2

B.Pt order: 1 > 2 > 3 > 4

MDJ Trick — M.Pt order

M.Pt: NH₃=1 | H₂O=1 | HF=2 (MDJ: 1 1 2)

Order same as B.Pt in group: 1 > 2 > 3 > 4

Properties Down the Group (Gp 15, 16)

Property	Trend (top to bottom)
E−H Bond Length	↑ se (increases)
E−H Bond Strength	↓ se (decreases)
E−H Bond dissociation	↓ se
H⁺ donation tendency (aq)	↑ se (acidic nature ↑)
Thermal Stability	↓ se
Acidic Nature	↑ se
pKa Value	↓ se
H removal tendency	↑ se (acid character)
Reducing Power	↑ se (top to bottom)
Bond Angle	↓ se (for Gp 15, 16 only)
L.P. Directional Nature	↓ se (for Gp 15, 16 only)
Lewis Basic Nature	↓ se (for Gp 15, 16 only)

🔬

ANOMALOUS BEHAVIOUR OF 2ND PERIOD P-BLOCK

2nd Period Elements: B, C, N, O, F

Reasons for anomalous behaviour:

Non-availability of d orbital in valence shell
Small size & factors related to size — I.E., E.N. etc.

Anomalous Behaviour of Fluorine

Fluorine — Key Anomalies

Main reasons: Small size, High E.N., Low F−F dissociation energy (LP−LP repulsion) & absence of vacant d' orbital
Most of reactions of F are exothermic
It forms only one oracid (HOF) shows +1 covalency
HF is liquid, others are gases
Fluorine can stabilize compound in higher O.S. due to its high oxidizing nature and high E.N.

CH₃OH vs Si(CH₃)OH — Back Bonding Effect

CH₃OH: No vacant orbital → No BB → LP free

Si(CH₃)OH: Has vacant d' → BB occurs → EN b/w Si and O ↑ → H removal tendency ↑ → Polarity ↑

⭐

IMPORTANT COMPOUNDS & SPECIAL POINTS

Oxides of Nitrogen

Compound	O.S.	State	Nature
N₂O	+1	Gas	Neutral (laughing gas)
NO	+2	Gas	Neutral
N₂O₃	+3	Liquid	Acidic (Blue)
NO₂	+4	Gas	Acidic (Brown)
N₂O₄	+4	Liquid/solid	Acidic
N₂O₅	+5	Solid	Acidic

N₂ [Dinitrogen Gas]

Colourless, odourless, tasteless
Non-toxic & Diamagnetic
Bond order = 3.0
Inert due to high B.D.E.
Prepared by fractional distillation of air
Liquid N₂ is used as refrigerant to preserve food items
Nitrogen cannot show allotropy (According to NCERT)

H₂SO₄ (Sulphuric Acid)

Conc. H₂SO₄

Acidic ✓
Dehydrating ✓
Oxidizing ✓
Viscous, High B.P.
Less volatile
Used as reagent
Bivalent ion SO₄²⁻

Dil. H₂SO₄

Acidic ✓
Dehydrating ✗
Oxidizing ✗

O₃ (Ozone)

Allotropic form of oxygen
Can't remain for long at sea level
Pure ozone: Pale blue (gas), Dark blue (liquid), Violet black (solid)
Thermodynamically highly unstable: 2O₃ → 3O₂ (ΔH=−ve, ΔS=−ve → High −ve ΔG)
Powerful Oxidizing agent

🌟

GROUP 18 — NOBLE GASES & XENON FLUORIDES

Group 18 — Physical Properties (He to Xe)

Property	Trend (He→Xe)
Mass	↑ se
Weak forces (W.V.F.)	↑ se (∝ mol. wt)
M.P. & B.P.	↑ se
Adsorption on charcoal surface	↑ se (size ↑)
Liquification tendency	↑ se
Solubility in water	↑ se (Top to bottom DID ↑)
Real gas character	↑ se
Ideal gas character	↓ se

Xenon Fluoride Compounds

Compound	Reaction	Hybridisation	Shape	Properties
XeF₂	Xe + F₂ (excess)	sp³d	Linear	Colourful crystalline solid, powerful fluorinating agent
XeF₄	Xe:F₂ = 1:5	sp³d²	Square Planar	Colourful crystalline solid
XeF₆	Xe:F₂ = 1:20	sp³d³	Distorted Octahedral	—

XeF₄ + O₂F₂ → XeF₆ + O₂ (Fluorinating agent)

Hydrolysis of Xenon Fluorides

XeF₂ + H₂O → Xe + HF + O₂

XeF₄ + H₂O → XeO₃ + Xe + HF + O₂

XeF₆ hydrolysis:

1H₂O → XeOF₄ + 2HF (partial)
2H₂O → XeO₂F₂ + 4HF (partial)
3H₂O → XeO₃ + 6HF (complete)

Fluorine Exchange Reactions of Xe Fluorides

Reaction	Products
XeF₂ + PF₅	[XeF]⁺ [PF₆]⁻
XeF₄ + SbF₅	[XeF₃]⁺ [SbF₆]⁻
XeF₆ + CsF	Cs⁺ [XeF₇]⁻
XeF₄ + RbF	Rb⁺ [XeF₅]⁻
XeF₄ + CsF	Cs⁺ [XeF₅]⁻
XeF₂ + BiF₅	[XeF]⁺ [BiF₆]⁻

MDJ

S-block (Alkalimetal) = F⁻ donor | P-block = F⁻ acceptor

📝

TRUE/FALSE & IMPORTANT MCQs

(I) PbO₂, Pb₂O₃ & Pb₃O₄ all are oxidizing agents — True/False?

✅ True — All contain Pb⁴⁺ which is O.A. (Pb⁴⁺→Pb²⁺)

(II) SnCl₂ & FeCl₃ can exist together — True/False?

✅ False — Sn²⁺ + Fe³⁺ → Sn⁴⁺ + Fe²⁺ (they react with each other)

(III) SnCl₂ is a good reducing agent — True/False?

✅ True — Sn²⁺ → Sn⁴⁺ (R.A.)

(IV) Tl⁺¹ is an example of oxidizing ion — True/False?

✅ False — Tl³⁺ → Tl⁺¹ (O.A., stable). Tl⁺¹ is already stable → not oxidizing ion.

(V) Both SO₂ & TeO₂ are oxidizing agents — True/False?

✅ False — SO₂: S⁴⁺→S⁶⁺ (R.A.) | TeO₂: Te⁴⁺→Te²⁺ (O.A.) — only TeO₂ is O.A.

(VI) PbI₄ does not exist — True/False?

✅ True — Pb⁴⁺ (O.A.) would oxidize I⁻ (R.A.) → PbI₂ forms instead

(VII) BiI₅ is more stable than BiF₅ — True/False?

✅ False — The only compound of Bi in its +5 O.S. is BiF₅

(VIII) TlI₃ cannot exist in any form — True/False?

✅ False — Case 1: Tl³⁺ + 3I⁻ not exist | Case 2: Tl⁺¹ + I₃⁻ (TlI₃) EXIST

(IX) PbX₄ is less stable than PbX₂ — True/False?

✅ True — Inert pair effect makes +2 more stable for Pb

(X) GeX₄ is more stable than GeX₂ — True/False?

✅ True — Ge is higher up in group, +4 is more stable

(XI) Oxidizing Power: C⁴⁺ < Si⁴⁺ < Ge⁴⁺ < Sn⁴⁺ < Pb⁴⁺ — True/False?

✅ True — Stability of H.O.S. ↓ down the group → tendency to get reduced ↑ → O.P. ↑

(XII) Both CO & CO₂ are reducing agents — True/False?

✅ False — CO: C²⁺→C⁴⁺ (R.A.) | CO₂: C⁴⁺ already stable (not R.A.)

P-BLOCK ELEMENTS

INTRODUCTION & INERT PAIR EFFECT

Inert Pair Effect

Stability of O.S. — Group wise

GROUP 13 — BORON FAMILY

Atomic Properties of Group 13

Chemical Reactivity of Group 13

BORAX, BORIC ACID & BACK BONDING

Borax [Na₂B₄O₇·10H₂O]

Orthoboric Acid [H₃BO₃]

Back Bonding in Boron Trihalide

DIBORANE [B₂H₆]

GROUP 14 — CARBON FAMILY

Atomic Properties

Chemical Properties of Group 14

ALLOTROPES OF CARBON

Allotropes of Phosphorus

Allotropes of Sulphur

GROUP 15 TO 18 — ATOMIC PROPERTIES

CHEMICAL REACTIVITY (GROUPS 15–17)

Reactivity with O₂

Reactivity with Halogens

HYDRIDES OF GROUPS 15, 16, 17

Boiling Point & Melting Point

Properties Down the Group (Gp 15, 16)

ANOMALOUS BEHAVIOUR OF 2ND PERIOD P-BLOCK

Anomalous Behaviour of Fluorine

IMPORTANT COMPOUNDS & SPECIAL POINTS

Oxides of Nitrogen

N₂ [Dinitrogen Gas]

H₂SO₄ (Sulphuric Acid)

O₃ (Ozone)

GROUP 18 — NOBLE GASES & XENON FLUORIDES

Group 18 — Physical Properties (He to Xe)

Xenon Fluoride Compounds

Hydrolysis of Xenon Fluorides

Fluorine Exchange Reactions of Xe Fluorides

TRUE/FALSE & IMPORTANT MCQs