Development of atomic modelsIB MYP Sciences: Flashcards

Exam questions on Development of atomic models

1. A science museum in Auckland is building a wall display that shows how scientists' ideas about the atom changed between 1803 and 1913. Each panel names a scientist, the date and the model of the atom that they proposed.
   Describe the plum pudding model of the atom proposed by J. J. Thomson after he discovered the electron in 1897.2 marks
2. In 1909, Hans Geiger and Ernest Marsden, working in Ernest Rutherford's laboratory in Manchester, fired a beam of alpha particles (small, positively charged particles) at a very thin sheet of gold foil. Most of the alpha particles passed straight through the foil. A small number were deflected through large angles, and about one in 8000 bounced almost straight back towards the source.
   Explain why the results of this experiment could not be explained by the plum pudding model.2 marks
3. A class in Singapore models the gold foil experiment. A small, hard, cone-shaped object is hidden under a flat cloth on a table. Students roll 50 identical marbles at the cloth from the same starting line, aiming along parallel lines spaced evenly across the cloth, and record the direction in which each marble leaves the cloth. Results: 41 marbles roll straight across, 7 are deflected slightly and 2 bounce back.
   Identify the independent variable, the dependent variable and one control variable in the students' investigation.3 marks