PREPWISER.
Practise online

p-Block Elements: Part II (Group 15-18) formula sheet

Every formula in the p-Block Elements: Part II (Group 15-18) chapter for JEE Main, with one line on when it applies. Topic 1 is open to everyone; sign in free to read all 27 and download the PDF.

Sign in to read all 27Download PDF

Read the first part free. Sign in free with Google to read the rest and download the PDF: 3 A4 pages.3 A4 pages, ready to print.

How we count: 7× asked means 7 past JEE Main questions in the PrepWiser bank needed that formula, and "last" is the latest year one appeared. ★ marks formulas asked 8 or more times.

Trends and anomalies across groups 15–18

Oxidation states
5× asked, last 2026
15: −3, +3, +516: −2, +2, +4, +617: −1, +1, +3, +5, +7\begin{aligned}&\text{15: }-3,\,+3,\,+5\qquad \text{16: }-2,\,+2,\,+4,\,+6\\&\text{17: }-1,\,+1,\,+3,\,+5,\,+7\end{aligned}
Inert pair: lower down, the state two below the maximum wins (Bi +3). Higher state more covalent: SbClX5>SbClX3\ce{SbCl5}>\ce{SbCl3}.
N, O, F are anomalous
13× asked, last 2026
N≡N vs PX4,O=O vs SX8max covalency of N, O=4\begin{aligned}&\ce{N#N}\ \text{vs}\ \ce{P4},\qquad \ce{O=O}\ \text{vs}\ \ce{S8}\\&\text{max covalency of N, O}=4\end{aligned}
Small, very electronegative, no d orbitals; pπp\pi–pπp\pi bonds. N–N, O–O, F–F are weaker than P–P, S–S, Cl–Cl.
Hydrides
14× asked, last 2026
NHX3>PHX3>AsHX3>SbHX3>BiHX3stability, basicity; angle 107.8∘→91.3∘b.p. (K): PHX3 185.5<AsHX3 210.6<NHX3 238.5b.p. (K): <SbHX3 254.6b.p. (K): HCl 189<HBr 206<HI 238<HF 293\begin{aligned}&\ce{NH3}>\ce{PH3}>\ce{AsH3}>\ce{SbH3}>\ce{BiH3}\\&\text{stability, basicity; angle }107.8^\circ\to91.3^\circ\\&\text{b.p. (K): }\ce{PH3}\ 185.5<\ce{AsH3}\ 210.6<\ce{NH3}\ 238.5\\&\phantom{\text{b.p. (K): }}<\ce{SbH3}\ 254.6\\&\text{b.p. (K): }\ce{HCl}\ 189<\ce{HBr}\ 206<\ce{HI}\ 238<\ce{HF}\ 293\end{aligned}
E–H weakens down a group: acidity (HI, HX2Te\ce{H2Te}) and reducing power (BiHX3\ce{BiH3}) rise. H-bonds lift NHX3\ce{NH3}, HX2O\ce{H2O}, HF.
Oxides
5× asked, last 2026
NX2OX3, PX4OX6 acidic;AsX2OX3, SbX2OX3 amphotericBiX2OX3 basic;acidity: EX2OX5>EX2OX3SOX2 reducing, TeOX2 oxidising\begin{aligned}&\ce{N2O3},\ \ce{P4O6}\ \text{acidic};\quad \ce{As2O3},\ \ce{Sb2O3}\ \text{amphoteric}\\&\ce{Bi2O3}\ \text{basic};\qquad \text{acidity: }\ce{E2O5}>\ce{E2O3}\\&\ce{SO2}\ \text{reducing},\ \ce{TeO2}\ \text{oxidising}\end{aligned}
Acidity falls down a group and rises with oxidation state. SFX6\ce{SF6} resists hydrolysis (F shields S).

Practise p-Block Elements: Part II (Group 15-18) questions as you read. Free, and you can start without signing up.

Practise p-Block Elements: Part II (Group 15-18)

23 more formulas in 5 topics

Group 15: nitrogen and its compounds; Group 15: phosphorus and its compounds; Group 16: ozone, sulphur, SO₂ and H₂SO₄; Group 17: halogens; and Group 18: noble gases. Read the first part free. Sign in free with Google to read the rest and download the PDF.

Sign in to read the restYou come straight back to this spot.Download the PDF

Group 15: nitrogen and its compounds

  • Dinitrogen7×
  • Ammonia2×
  • Nitric acid: Ostwald4×
  • HNO₃ with metals
  • Oxides of nitrogen12×

Group 15: phosphorus and its compounds

  • Allotropes of phosphorus3×
  • Phosphine4×
  • PCl₃ and PCl₅6×
  • Oxoacids of phosphorus11×

Group 16: ozone, sulphur, SO₂ and H₂SO₄

  • Ozone1×
  • Allotropes of sulphur5×
  • Sulphur dioxide3×
  • Sulphuric acid1×
  • Oxoacids of sulphur4×

Group 17: halogens

  • Halogen trends3×
  • Halogens as oxidants6×
  • Cl₂ with alkali
  • HCl and HX acidity2×
  • Oxoacids of halogens4×
  • Interhalogens3×

Group 18: noble gases

  • Noble gases2×
  • Xenon fluorides3×
  • Hydrolysis of xenon fluorides

Practise p-Block Elements: Part II (Group 15-18) next

About 105 past JEE Main questions from this chapter, with instant answer checking and step-by-step solutions where available. Free, and you can start without signing up.

Practise p-Block Elements: Part II (Group 15-18)

Also free on PrepWiser

Spotted a mistake? Write to support@prepwiser.in and we will fix it in the next version.

Version 1, October 2026. Free to share for study, as it is. Please don't sell it or remove the PrepWiser name.

PractiseSign in to read all 27Download PDF
Free with Google, takes a few seconds3 pages, free