Absorption & Emission Of Radiation (AQA GCSE Combined Science: Synergy: Life & Environmental Sciences): Revision Note

Absorption & Emission Of Radiation

• Electrons in an atom are arranged in energy levels

  • Lower energy levels are closer to the nucleus, whilst higher energy levels are further away from the nucleus of the atom

• These electrons can absorb energy

• This happens when waves of electromagnetic radiation (such as light and heat) hit them

• When electrons absorb electromagnetic radiation, they move to a higher energy level

The electron absorbs electromagnetic radiation which causes it to move up an energy level

Emission of Electromagnetic Radiation

• When an electron has moved up an energy level, it will be unstable

• Eventually, it will move back down to its original energy level, which will be closer to the nucleus

• As it moves back down, It emits a wave of electromagnetic radiation

  • The frequency of the emitted radiation depends on the size of the energy jump

  • A larger energy jump produces radiation with a higher frequency

The electron emits a wave of electromagnetic radiation and moves down an energy level

• All of the colours in the visible spectrum are produced in this way

• The light waves come from electrons moving down energy levels and emitting electromagnetic radiation

• Atoms of different elements emit radiation at characteristic frequencies:

  • Atoms such as neon and sodium emit light in the visible region of the spectrum

  • Atoms such as mercury emit radiation in the ultraviolet region