DP Chemistry (first assessment 2025)

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Question 21N.1A.SL.TZ0.11

Date	November 2021	Marks available	[Maximum mark: 1]	Reference code	21N.1A.SL.TZ0.11
Level	SL	Paper	1A	Time zone	TZ0
Command term	Interpret	Question number	11	Adapted from	N/A

11.

[Maximum mark: 1]

21N.1A.SL.TZ0.11

Which compound contains both ionic and covalent bonds?

A. CH₃COONa

B. CH₃COOH

C. K₂O

D. CaCl₂

[1]

Markscheme

A

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.

Structure 2. Models of bonding and structure » Structure 2.1—The ionic model » Structure 2.1.2—The ionic bond is formed by electrostatic attractions between oppositely charged ions. Deduce the formula and name of an ionic compound from its component ions, including polyatomic ions. Binary ionic compounds are named with the cation first, followed by the anion. The anion adopts the suffix “ide”. Interconvert names and formulas of binary ionic compounds.