DP Chemistry (first assessment 2025)
Question 21N.2.SL.TZ0.a
| Date | November 2021 | Marks available | [Maximum mark: 2] | Reference code | 21N.2.SL.TZ0.a |
| Level | SL | Paper | 2 | Time zone | TZ0 |
| Command term | Suggest | Question number | a | Adapted from | N/A |
a.
[Maximum mark: 2]
21N.2.SL.TZ0.a
Suggest what can be concluded about the gold atom from this experiment.
[2]
Markscheme
Most 4He2+ passing straight through:
most of the atom is empty space
OR
the space between nuclei is much larger than 4He2+ particles
OR
nucleus/centre is «very» small «compared to the size of the atom» ✔
Very few 4He2+ deviating largely from their path:
nucleus/centre is positive «and repels 4He2+ particles»
OR
nucleus/centre is «more» dense/heavy «than 4He2+ particles and deflects them»
OR
nucleus/centre is «very» small «compared to the size of the atom» ✔
Do not accept the same reason for both M1 and M2.
Accept “most of the atom is an electron cloud” for M1.
Do not accept only “nucleus repels 4He2+ particles” for M2.
Syllabus sections
Structure 1. Models of the particulate nature of matter » Structure 1.2—The nuclear atom » Structure 1.2.1 - Atoms and negatively charged electrons. Atoms contain a positively charged, dense nucleus composed of protons and neutrons (nucleons). Negatively charged electrons occupy the space outside the nucleus. Use the nuclear symbol ZXA to deduce the number of protons, neutrons and electrons in atoms and ions.