DP Chemistry (first assessment 2025)
Question 22M.2.HL.TZ2.3d(i)
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.2.HL.TZ2.3d(i) |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Draw | Question number | d(i) | Adapted from | N/A |
d(i).
[Maximum mark: 1]
22M.2.HL.TZ2.3d(i)
(d(i))
Draw the Lewis structure of NO3−.
[1]
Markscheme
Do not accept the delocalised structure.
Accept any combination of dots, crosses and lines.
Coordinate/dative bond may be represented by an arrow.
Examiners report
Only 20% of the candidates scored the mark for the Lewis structure of NO3-. Mistakes included: missing charge, missing lone pairs, 3 single bonds, 2 double bonds.
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.