Question 22N.2.hl.TZ0.f.v
| Date | November 2022 | Marks available | [Maximum mark: 3] | Reference code | 22N.2.hl.TZ0.f.v |
| Level | hl | Paper | 2 | Time zone | TZ0 |
| Command term | Deduce | Question number | f.v | Adapted from | N/A |
Ammonium nitrate, NH4NO3, is used as a high nitrogen fertilizer.
Solid ammonium nitrate can decompose to gaseous dinitrogen monoxide and liquid water.
Deduce the Lewis (electron dot) structure, including formal charges, and shape for dinitrogen monoxide showing nitrogen as the central atom.
[3]
Alternative 1
Lewis structure:
✔
+/1+/+1 on central N atom AND –/1–/–1 on O atom ✔
Alternative 2
Lewis structure:
✔
+/1+/+1 on central N atom AND –/1–/–1 on other N atom ✔
Shape: linear ✔
Accept 
.
Formal charges are not needed for M1.
Allow ECF for both formal charge and shape.
Only award M3 if the shape corresponds to that expected for the Lewis structure given.
Students on average gained about half marks. Many seemed to be in one of two camps; those that knew of the resonance structures of the molecule, and usually scored 3 marks, and those who gained zero because they did not, though occasionally the latter group would score one of the other marks as an ECF.