DP Chemistry (first assessment 2025)

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Question 21M.1A.HL.TZ2.12

Date	May 2021	Marks available	[Maximum mark: 1]	Reference code	21M.1A.HL.TZ2.12
Level	HL	Paper	1A	Time zone	TZ2
Command term	Identify	Question number	12	Adapted from	N/A

12.

[Maximum mark: 1]

21M.1A.HL.TZ2.12

Which atom has an expanded octet?

A. C in CO₂

B. S in SCl₄

C. O in H₂O₂

D. P in PCl₃

[1]

Markscheme

B

Syllabus sections

Structure 2. Models of bonding and structure » Structure 2.2—The covalent model » Structure 2.2.13—Some atoms can form molecules in which they have an expanded octet of electrons. Visually represent Lewis formulas for species with five and six electron domains around the central atom. Deduce the electron domain geometry and the molecular geometry for these species using the VSEPR model.