Practice Question

1. A sample of sodium is placed into a roaring blue bunsen burner flame. A yellow flame colour is then seen. Explain the origin of the yellow flame colour.

When the sodium is placed into the roaring blue bunsen burner flame it absorbs EM radiation. This will cause an electron to move from a lower energy level to a higher energy level. However, the electron is unstable in the higher energy level, so it will drop down to a lower energy level and emit electromagnetic waves in the form of visible light

2. Many sunscreen products contain UV absorbing chemicals. Suggest how these could work to protect a person from UV rays.

The chemicals in the sunscreen absorb UV radiation, causing an electron in one of the energy levels to be promoted to a higher energy. This removes the energy of the UV radiation. 

3. Explain why an alpha emitter can also emit gamma rays. 

After an alpha emission, the nucleus may be excited with excess energy, so it emits a gamma ray, which will decrease the energy of the nucleus.