DP Chemistry (first assessment 2025)

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Question 19N.1A.SL.TZ0.13

Date	November 2019	Marks available	[Maximum mark: 1]	Reference code	19N.1A.SL.TZ0.13
Level	SL	Paper	1A	Time zone	TZ0
Command term	Determine	Question number	13	Adapted from	N/A

13.

[Maximum mark: 1]

19N.1A.SL.TZ0.13

Which atom does not obey the octet rule?

A. C in CO₂

B. F in BF₃

C. O in H₂O

D. S in SF₆

[1]

Markscheme

D

Syllabus sections

Structure 2. Models of bonding and structure » Structure 2.2—The covalent model » Structure 2.2.1—A covalent bond is formed by the electrostatic attraction between a shared pair of electrons and the positively charged nuclei. The octet rule refers to the tendency of atoms to gain a valence shell with a total of 8 electrons. Deduce the Lewis formula of molecules and ions for up to four electron pairs on each atom.