HALF QUESTION Typical of Question 12 in Leaving Cert. Exam
Q6 Answer both of the following parts (a) and (b).
(a) Fig 22.28 shows a simplified arrangement of an experiment to investigate the structure of the atom.The investigation was performed by Hans Geiger and Ernest Marsden in 1909, under the direction of Ernest Rutherford. It involved firing alpha particles at a thin sheet of gold foil in a vacuum.
(i) What are alpha particles? (6)
(ii) Describe what happened to the alpha particles during the experiment. (6)
(iii) What was the purpose of the zinc sulphide screen in this experiment and how did it perform this role?
Fig 22.28
(iv) What conclusion did the scientists make about the structure of the atom? (v) Why was it necessary to carry out this experiment in a vacuum? (b) Describe the Bohr model of the atom.
Describe how an emission line spectrum is produced.
Why does a metal emit a continuous spectrum rather than a line spectrum? Give a practical use of line spectra.
