PractifyUs

NEET Chemistry · p-Block Elements

Group 15 and Group 16 elements

Taught in NCERT Class 12 Chemistry, Chapter 7: The p-Block Elements.

2 verified questions: Easy 0 · Medium 2 · NEET level 0

Sample questions

Sample 1Medium

White phosphorus is drawn as discrete molecules in which four phosphorus atoms sit at the corners of a regular tetrahedron, each atom joined by single bonds to the other three. Which statement follows from this structure?

  1. A

    Each P–P–P angle is 109.5°, so the molecule is unstrained and less reactive than red phosphorus

  2. B

    Each P atom has no lone pair, so white phosphorus is chemically inert

  3. C

    The P4 tetrahedra are joined in chains, giving a polymeric solid

  4. D

    Each P–P–P angle is 60°, so the molecule is strained and white phosphorus is more reactive than red phosphorus

Show the answer
The answer is D.

In the P4 tetrahedron each face is an equilateral triangle, so the P–P–P angle is 60°. This angular strain makes white phosphorus less stable and more reactive than the polymeric red phosphorus.

  • A.

    Atoms at the corners of a tetrahedron, bonded along its edges, form equilateral triangles with 60° angles, which causes strain.

  • B.

    Each P atom uses three electrons in bonds and keeps one lone pair; white phosphorus is very reactive.

  • C.

    Chains of linked P4 units describe red phosphorus; white phosphorus consists of discrete P4 molecules.

NCERT: Class 12 Chemistry (2022 edition), Chapter 7: The p-Block Elements

Practise Group 15 and Group 16 elements

Practice at the level you choose, with the answer after every question; timed tests with the answers when you submit. Every question is verified against NCERT first.

Sign in to practise

More in p-Block Elements