9th Chemistry Chapter2 Structure of Atoms

1. Explain the role of isotopes in radiometric dating.

Radiometric dating relies on the decay of isotopes to determine the age of rocks or fossils. The ratio of parent to daughter isotopes is used to estimate the time elapsed since the material formed.

Describe the shorthand notation used to represent electronic configurations.

Shorthand notation uses noble gas abbreviations to represent the core electrons, followed by the valence electrons. For example, the electronic configuration of sulfur (S) is written as [Ne] 3s² 3p⁴.

2. How does Bohr's model explain the spectral lines observed for hydrogen atoms?

Bohr’s model explains the spectral lines by stating that electron in hydrogen atoms transition between energy levels, emitting or absorbing photons with energy equal to the energy difference between the levels. The observed lines correspond to different energy transitions.

Discuss the limitations of Bohr's atomic model.

Bohr’s model was successful for hydrogen-like atoms but failed to explain the spectra of multi-electron atoms. It did not account for electron-electron interactions and the complexities of atoms beyond hydrogen.

3. What were the key postulates of Bohr's atomic model?

Bohr’s atomic model proposed that electrons orbit the nucleus in fixed energy levels or orbits. Electrons can only occupy these quantized orbits, and transitions between orbits result in the absorption or emission of energy.

What were the limitations of Rutherford's atomic model?

Rutherford’s model could not explain the stability of electrons in orbit around the nucleus, as accelerating charged particles should emit radiation and lose energy. This limitation was addressed by later quantum models.