An emission spectrum is generated by the release of energy of valence electrons moving from an excited state to ground state.

The emission spectrum generated by a particular element is unique to that element and can be used in forensic investigations to identify the element present.

The emission spectra of some elements are shown below.

Hydrogen
Helium
Carbon
Sulfur
Copper
Iron

View the video on the left
1) An electron can absorb heat energy only heat and light energy light energy only

2) When an electron absorbs energy it spirals into the nucleus it always escapes the atom it jumps to higher energy states closer to the nucleus it jumps to energy levels further from the nucleus

3) An electron that has absorbed energy and move to a higher energy state is most likely to release the energy it has absorbed as light of a particular colour escape the atom keep absorbing energy and move to higher energy levels until it escapes the atom.

4) Explain how dark lines appear in the spectrum of white light passing through a cloud of hydrogen gas.

5) How is an emission and an absorption spectrum similar?

6) Using the hydrogen emission spectrum explain how an emission spectrum is formed.

7) Deep ultra violet light is given off when protons jump from higher energy levels to the n=1 energy level. transitions of electrons from higher energy levels to the n=2 energy level. is more energetic than violet light and is emitted when an electron jumps from higher energy levels to the n=1 energy level.

8) A photon of red light involves high energy in the infrared region of the spectrum. high energy in the ultra violet region of the visible spectrum low energy

9) Looking at the diagram below, which statement is true? Energy in the infrared region is most likely emitted when an electron moves from n=7 to n=5 Energy in the infrared region is most likely emitted when a proton moves from n=7 to n=2 Energy in the infrared region is most likely emitted when an electron moves from n=7 to n=2 Energy in the infrared region is most likely emitted when a proton moves from n=7 to n=2

But the hydrogen electron doesn't only have the electron jumps that cause spectral lines in the visible region but also in the UV and infrared regions.

As you can see from the diagram on the left, a number of jumps are possible

If an electron falls from the 3-level to the 2-level, red light is seen. This is the origin of the red line in the hydrogen spectrum. By measuring the frequency of the red light, you can work out its energy. That energy must be exactly the same as the energy gap between the 3-level and the 2-level in the hydrogen atom.