NEET ChemistryUpdated 19 Oct 2026

p-Block Elements (Group 15 to 18): NEET PYQs and weightage

p-Block Elements (Group 15 to 18) carries 3.5 of 100 Chemistry marks in NEET by past-paper share: 25 of the 707 tagged NEET Chemistry PYQs in the ViJEEta bank (NEET 2013–2026). It ranks 13 of 26 Chemistry chapters.

Take the 25-question p-Block Elements (Group 15 to 18) test Key facts ↓All NEET Chemistry chapters

3.5/100 Weight in Chemistry

Exam importance (3/5, by past-paper share)

25 NEET PYQs

262 Practice questions

173 With measured difficulty

How the weight is computed: this chapter's tagged NEET PYQs divided by all tagged NEET Chemistry PYQs in the bank (25 of 707), times 100, with repeated questions counted once. The bank does not store the year of each NEET question, so none is printed. Computed from the bank at build time. Updated 19 Oct 2026.

p-Block Elements (Group 15 to 18): key facts for NEET

16 facts the paper keeps asking, each with how it is asked. Copy it onto one page of your notebook: that page is this chapter's handbook.

Highest oxidation state and inert pair effect
$Highest oxidation state = group number - 10$
Down groups 13–16, the state two lower gets more stable (inert pair effect).
Asked as: stability of $+ 1$ increases $Al < Ga < In < Tl$ ; $+ 2$ increases $Ge < Sn < Pb$ .
Anomalous first member
The first member differs from its group (small size, high electronegativity, no $d$ orbitals), so boron's maximum covalency is $4$ .
Asked as: which anion can boron NOT form? $[B F_{6}]^{3 -}$
Atomic radius of Ga < Al
$Ga$ ( $135 pm$ ) is smaller than $Al$ ( $143 pm$ ) because its $10$ extra $d$ -electrons shield the outer electrons poorly.
Asked as: reason for the atomic radius of $Ga < Al$ (poor screening by $d$ -electrons).
Group 13 ionisation enthalpy
Group 13 ionisation enthalpy does not fall smoothly (breaks at $Al \to Ga$ and $In \to Tl$ from $d$ and $f$ electrons): $B > Tl > Ga > Al > In$ .
Asked as: arrange $B$ , $Al$ , $Ga$ , $In$ , $Tl$ by first ionisation enthalpy.
Low melting point of gallium
Gallium melts at only $303 K$ , so it can be liquid in summer.
Asked as: which group 13 element has an unusually low melting point?
Nature of group 13 oxides
$B_{2} O_{3}$ is acidic, $A l_{2} O_{3}$ and $G a_{2} O_{3}$ are amphoteric, $I n_{2} O_{3}$ and $T l_{2} O_{3}$ are basic.
Asked as: which group 13 oxide is acidic? $B_{2} O_{3}$
Reactions of aluminium
$Al$ gives $H_{2}$ with both dilute $HCl$ and aqueous $NaOH$ (amphoteric), but conc. $HN O_{3}$ makes it passive through an oxide layer.
Asked as: why $Al$ resists corrosion / why conc. $HN O_{3}$ does not dissolve $Al$ .
Group 13 trihalides as Lewis acids
The monomeric group 13 trihalides are electron deficient, so they are strong Lewis acids; $Tl I_{3}$ is the exception and is not formed; $AlC l_{3}$ dimerises to $A l_{2} C l_{6}$ but boron halides do not.
Asked as: why $BC l_{3}$ is a Lewis acid / why boron halides do not dimerise.
Carbon-14
$^{14} C$ is radioactive with a half-life of $5770$ years and is used in radiocarbon dating (stable isotopes are $^{12} C$ and $^{13} C$ ).
Asked as: half-life or use of $^{14} C$ .
Stability of +2 in group 14
Stability of $+ 2$ rises $Ge < Sn < Pb$ (inert pair effect), so $Pb X_{2}$ is more stable than $Pb X_{4}$ , and $Pb I_{4}$ does not exist.
Asked as: which tetrahalide is not known? $Pb I_{4}$
Nature of group 14 oxides
$CO$ is neutral; $C O_{2}$ , $Si O_{2}$ , $Ge O_{2}$ are acidic; $Sn O_{2}$ , $Pb O_{2}$ , $SnO$ , $PbO$ are amphoteric; $GeO$ is acidic.
Asked as: pick the neutral oxide / the amphoteric dioxides of group 14.
Action of steam on Sn and Pb
Tin decomposes steam to give $Sn O_{2} + H_{2}$ , while lead is unaffected by water because of a protective oxide film.
Asked as: identify $X$ in $X + 2 H_{2} O (steam) \to X O_{2} + 2 H_{2}$ ( $Sn$ ).
Hydrolysis of tetrachlorides
All tetrachlorides except $CC l_{4}$ hydrolyse easily, because the central atom takes the lone pair from water's $O$ into its $d$ orbital.
Asked as: why $CC l_{4}$ is not hydrolysed but $SiC l_{4}$ is (no $d$ orbitals in $C$ ).
Catenation
Catenation: $C ≫ Si > Ge \approx Sn$ , and $Pb$ shows none; the $C - C$ bond is the strongest ( $348 kJ mo l^{- 1}$ ).
Asked as: element with maximum catenation / reason (strong $C - C$ bond).
Diamond and graphite
Diamond: $s p^{3}$ $C$ , tetrahedral 3-D network, $C - C$ $154 pm$ , hardest substance. Graphite: $s p^{2}$ layers held by van der Waals forces $340 pm$ apart, $C - C$ $141.5 pm$ , conducts along the sheet.
Asked as: hybridisation of $C$ in graphite / force between graphite layers.
Fullerene and most stable allotrope
Fullerene $C_{60}$ (buckminsterfullerene) has $20$ six-membered and $12$ five-membered rings, with all $C$ atoms $s p^{2}$ ; graphite is the thermodynamically most stable allotrope.
Asked as: number of 5- and 6-membered rings in $C_{60}$ / most stable allotrope of carbon.

Trap

The group oxidation state is NOT the most stable one for the heavy members. Because of the inert pair effect, Tl prefers +1 over +3 and Pb prefers +2 over +4.

How does NEET ask p-Block Elements (Group 15 to 18)?

8 real previous-year questions from this chapter, as printed in the paper, each with its worked solution. Answer the first one here with no sign-in.

Q1ChemistryNEET UG PYQChemical Properties of Group 16 Elements

Try right here · No sign-in

Match List - I with List – II List – IList - II(a) 2SO

_{2}

(g) + O

_{2}

(g) ⟶ 2SO

_{3}

(g)(i) Acid rain(b) HOCl(g)

hv

HO + Cl(ii) Smog(c) CaCO

_{3}

+ H

_{2}

_{4}

⟶ CaSO

_{4}

+ H

_{2}

O + CO

_{2}

(iii) Ozone depletion(d) NO

_{2}

(g)

hv

NO(g) + O(g)(iv) Tropospheric pollution

Choose the correct answer from the options given below:

Answer key (A) & worked solution

Correct answer: Option A

(a) represents tropospheric pollution due to burning of substances containing sulphur (b) represents one of the steps in ozone layer depletion (c) represents effect of acid rain on marble. (d) represents the formation of smog

Q2ChemistryNEET UG PYQPhysical Properties of Group 16 Elements

Given below are two statements: Statement I: The boiling point of hydrides of Group 16 elements follow the order H

_{2}

O > H

_{2}

Te > H

_{2}

Se > H

_{2}

S Statement II: On the basis of molecules mass, H

_{2}

O is expected to have lower boiling point than the other members of the group but due to the presence of extensive H-bonding in H

_{2}

O. It has higher boiling point. In the light of the above statements, choose the correct answer from the options given below:

ABoth statement I and statement II are false

BStatement I is true but statement II is false

CStatement I is false but statement II is true

DBoth statement I and statement II are true.

Answer key (D) & worked solution

Correct answer: Option D

(d) Both statement I and statement II are true.

Q3ChemistryNEET UG PYQChemical Properties of Group 17 Elements

Given below are two statements : Statement-I: Heating NaCl with concentrated

H_{2} SO_{4}

and

MnO_{2}

results in oxidation of Mn . Statement-II: Heating NaI with concentrated

H_{2} SO_{4}

and

MnO_{2}

results in reduction of Mn . In light of the above statements, choose the most appropriate answer from the options given below.

ABoth Statement-I and Statement-II are incorrect

BStatement-I is correct but Statement-II is incorrect

CStatement-I is incorrect but Statement-II is correct

DBoth Statement-I and Statement-II are correct

Answer key (C) & worked solution

Correct answer: Option C

Statement-I : (False)

2 NaCl + + 4 n O_{2} + 4 + 2 H_{2} SO_{4} \to Na_{2} SO_{4} + MnSO_{4} + 2 + 2 H_{2} O + Cl_{2}

So, reduction of Mn is taking place. Statement-II : (True)

2 NaI + MnO + 4 O_{2} + 2 H_{2} SO_{4} \to Na_{2} SO_{4} + MnSO + 2 + I_{2} + 2 H_{2} O

So, Mn has undergone reduction.

Q4ChemistryNEET UG PYQChemical Properties of Group 15 Elements

When copper is heated with conc. HNO

_{3}

it produces?

ACu(NO

_{3}

)

_{2}

and N

_{2}

BCu(NO

_{3}

)

_{2}

and NO

_{2}

CCu(NO

_{3}

)

_{2}

and NO

DCu(NO

_{3}

)

_{2}

, NO and NO

_{2}

Answer key (B) & worked solution

Correct answer: Option B

\begin{gathered} Cu + \mathop {4HN{O_3}}\limits_{conc.} \to Cu{\left( {N{O_3}} \right)_2} + \mathop {2N{O_2}}\limits_{Brown\,\,gas} + 2{H_2}O \\ \left[ {\begin{array}{*{20}{c}} {Cu + conc.\,HN{O_3} \to N{O_2}} \\ {Cu + dil.\,HN{O_3} \to NO} \end{array}} \right. \\ \end{gathered}

Q5ChemistryNEET UG PYQChemical Properties of Group 16 Elements

Roasting of sulphides gives the gas X as a byproduct. This is a colorless gas with choking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic acts as a reducing agent and its acid has never been isolated. The gas X is

_{2}

BSO

_{2}

CCO

_{2}

DSO

_{3}

Answer key (B) & worked solution

Correct answer: Option B

Zinc blende 2 Z n S + 3 O_{2} \to 2 Z n O + 2 S O_{2}

Galena 2 P b S + 3 O_{2} \to 2 P b O + 2 S O_{2}

Copper glance 2 C u_{2} S + 3 O_{2} \to 2 C u_{2} O + 2 S O_{2}

Q6ChemistryNEET UG PYQChemical Properties of Group 17 Elements

Assertion (A): ICl is more reactive than I

_{2}

Reason(R): I-Cl bond is weak than I-I bond Choose the most appropriate answer from the options given below:

ABoth (A) and (R) are correct and (R) is the correct explanation of (A)

BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)

C(A) is correct but (R) is not correct

D(A) is not correct but (R) is correct

Answer key (A) & worked solution

Correct answer: Option A

Both (A) and (R) are correct and (R) is correct explanation of (A) Interhalogen species are more reactive than halogens, so A is right. In general, interhalogens compounds are more reactive than halogens (except F). This is because X-X’ bond in interhalogens in weaker than X-X bond in halogens except F-F bond.

Q7ChemistryNEET UG PYQPhysical Properties of Group 18 Elements

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Helium is used to dilute oxygen in diving apparatus. Reason R : Helium has high solubility in O

_{2}

. In the light of the above statements, choose the correct answer from the options given below :

ABoth A and R are true, but R is NOT the correct explanation of A

BA is true but R is false

CA is false but R is true

DBoth A and R are true and R is the correct explanation of A

Answer key (B) & worked solution

Correct answer: Option B

Assertion is true because He has low solubility in blood.

Q8ChemistryNEET UG PYQChemical Properties of Group 17 Elements

Match the interhalogen compounds of column I with the geometry in column II and assign the correct code:Column I Column II(a) XX' (i) T- shape

(b) XX'

_{3}

(ii) Pentagonal bipyramidal

(C) XX'

_{5}

(iii) Linear

(d) XX'

_{7}

(iv) Square-pyramidal

(v) Tetrahedral

A(a)-(v); (b)-(iv); (c)-(iii); (d)-(ii)

B(a)-(iv); (b)-(iii); (c)-(ii); (d)-(i)

C(a)-(iii); (b)-(iv); (c)-(i); (d)-(ii)

D(a)-(iii); (b)-(i); (c)-(iv); (d)-(ii)

Answer key (D) & worked solution

Correct answer: Option D

XX ′ → Linear XX’

_{3}

→ Example : CIF

_{3}

→ T-shape XX’

_{5}

→ Example : BrF

_{5}

→ Square-pyramidal XX’

_{7}

→ Example : IF

_{7}

→ Pentagonal bipyramidal

Which topics in p-Block Elements (Group 15 to 18) carry the most questions?

The 12 busiest of 13 topics, by tagged PYQs, then practice questions. Counted from the bank. Updated 19 Oct 2026.

Topic	PYQs	Practice questions
Chemical Properties of Group 16 Elements	8	45
Chemical Properties of Group 15 Elements	6	90
Chemical Properties of Group 17 Elements	5	54
Physical Properties of Group 16 Elements	2	5
Introduction to Group 18 Elements	1	17
Physical Properties of Group 18 Elements	1	12
Introduction to Group 15 Elements	1	8
Physical Properties of Group 17 Elements	1	6
Physical Properties of Group 15 Elements	0	12
Miscellaneous Examples	0	9
Introduction to Group 16 Elements	0	2
Introduction to Group 17 Elements	0	1

Why does p-Block Elements (Group 15 to 18) show "–" until you answer 3 questions?

Unknown is not zero. Until you answer at least 3 graded questions in p-Block Elements (Group 15 to 18), ViJEEta shows – instead of a zero or a 50% default. Book exercises can raise chapter mastery up to 0.60, adaptive practice up to 0.75, and only a timed chapter test or mock can certify 0.80 and above.

How ViJEEta scores you

What happens when you test p-Block Elements (Group 15 to 18)?

Every chapter test is 25 questions. It starts at moderate difficulty and adapts after each saved answer. If you open a solution before answering, that attempt earns no credit, so your mastery stays honest.

Start the p-Block Elements (Group 15 to 18) test

Chapters either side of p-Block Elements (Group 15 to 18) by weight

Biomolecules Weight 4.1/100 Aldehydes and Ketones Weight 4.0/100 Ionic Equilibrium Weight 3.4/100 Some Basic Concepts of Chemistry Weight 3.4/100

p-Block Elements (Group 15 to 18): NEET PYQs and weightage

p-Block Elements (Group 15 to 18): key facts for NEET

Highest oxidation state and inert pair effect

Anomalous first member

Atomic radius of Ga < Al

Group 13 ionisation enthalpy

Low melting point of gallium

Nature of group 13 oxides

Reactions of aluminium

Group 13 trihalides as Lewis acids

Carbon-14

Stability of +2 in group 14

Nature of group 14 oxides

Action of steam on Sn and Pb

Hydrolysis of tetrachlorides

Catenation

Diamond and graphite

Fullerene and most stable allotrope

How does NEET ask p-Block Elements (Group 15 to 18)?

Which topics in p-Block Elements (Group 15 to 18) carry the most questions?

Why does p-Block Elements (Group 15 to 18) show "–" until you answer 3 questions?

What happens when you test p-Block Elements (Group 15 to 18)?

Chapters either side of p-Block Elements (Group 15 to 18) by weight