Date | November 2021 | Marks available | 2 | Reference code | 21N.2.sl.TZ0.8 |
Level | SL | Paper | 2 | Time zone | TZ0 |
Command term | Sketch | Question number | 8 | Adapted from | N/A |
Question
Fast moving helium nuclei (4He2+) were fired at a thin piece of gold foil with most passing undeflected but a few deviating largely from their path. The diagram illustrates this historic experiment.
Figure from PPLATO / FLAP (Flexible Learning Approach To Physics), http://www.met.reading.ac.uk/pplato2/h-flap/
phys8_1.html#top 1996 The Open University and The University of Reading.
Suggest what can be concluded about the gold atom from this experiment.
Subsequent experiments showed electrons existing in energy levels occupying various orbital shapes.
Sketch diagrams of 1s, 2s and 2p.
State the electron configuration of copper.
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.
1s AND 2s as spheres ✔
one or more 2p orbital(s) as figure(s) of 8 shape(s) of any orientation (px, py pz) ✔
1s22s22p63s23p64s13d10
OR
[Ar] 4s13d10 ✔
Accept configuration with 3d before 4s.