DP Chemistry (first assessment 2025)

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Question 22M.2.HL.TZ2.7b(ii)

Date	May 2022	Marks available	[Maximum mark: 1]	Reference code	22M.2.HL.TZ2.7b(ii)
Level	HL	Paper	2	Time zone	TZ2
Command term	Identify	Question number	b(ii)	Adapted from	N/A

b(ii).

[Maximum mark: 1]

22M.2.HL.TZ2.7b(ii)

(b(ii))

Identify the number of sigma and pi bonds in HCN.

[1]

Markscheme

Sigma ( $σ$ ): 2 AND Pi ( $π$ ): 2 ✔

Syllabus sections

Structure 2. Models of bonding and structure » Structure 2.2—The covalent model » Structure 2.2.15—Sigma bonds σ form by the head-on combination of atomic orbitals where the electron density is concentrated along the bond axis. Pi bonds π form by the lateral combination of p-orbitals where the electron density is concentrated on opposite sides of the bond axis. Deduce the presence of sigma bonds and pi bonds in molecules and ions.