Assertion and reason: models

Exercise and reference answers

Questions

1. Reason

   Classical physics predicts any orbiting electron must radiate.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   Bohr had to postulate stationary orbits rather than derive them.

2. Reason

   Each element emits its own characteristic set of lines.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   Line spectra are useful evidence about atomic structure.

3. Reason

   An atom as a whole is electrically neutral.

   Verdict

   The assertion is false and the reason is true.

   Assertion

   Thomson's model explains scattering results.

Explanation