The range of radiation from radio waves to gamma rays, ordered by wavelength and energy.
Practise Atomic Structure & Periodicity All Atomic Structure & Periodicity topics
The electromagnetic spectrum is the full range of radiation ordered by wavelength and frequency, from long-wavelength radio waves to short-wavelength gamma rays. Photon energy rises as wavelength falls, so a gamma-ray photon carries far more energy than a radio photon. Different regions probe different kinds of motion: microwave radiation drives molecular rotation, infrared drives vibration, visible and ultraviolet light drive electronic transitions, and X-rays excite inner electrons. The visible region spans roughly 400 to 700 nm. Spectroscopic techniques exploit these regions to learn about molecular structure.
Key ideas: Order by increasing frequency: radio, microwave, infrared, visible (about 700 nm red to 400 nm violet), ultraviolet, X-ray, gamma. Rough wavelengths: radio over 1 m, microwave 1 mm to 1 m, IR 700 nm to 1 mm, UV 10 to 400 nm, X-rays 0.01 to 10 nm. Interactions: microwaves rotate molecules, IR vibrates bonds, UV-vis excites electrons, X-rays eject inner electrons.
Common mistakes and connections: Students think visible light is a large part of the spectrum, when it is a narrow band, and that red light has more energy than violet (it has less). Also, microwaves heating is not due to radiation breaking bonds. This leads to spectroscopy techniques such as IR, NMR and UV-vis.
The spectrum spans wavelengths from picometer gamma rays to radio waves of hundreds of meters, with visible light a tiny band near 400 to 700 nm. The interactive lesson shows this as a live animation or chart.
Ultraviolet photons carry enough energy to break chemical bonds and damage DNA, whereas infrared photons only make bonds vibrate.
The range of radiation from radio waves to gamma rays, ordered by wavelength and energy.
Electromagnetic Spectrum is a beginner topic in Atomic Structure & Periodicity. It needs no earlier chemistry lessons and is a good starting point.
Study these earlier topics in Atomic Structure & Periodicity first: Millikan's Oil Drop Experiment, Electromagnetic Radiation, Wavelength and Frequency.
The next topics in Atomic Structure & Periodicity are Black Body Radiation and Planck's Quantum Theory.
Yes. The interactive lesson includes a self-check question on Electromagnetic Spectrum, and the Atomic Structure & Periodicity quiz draws on every topic in this area.
Electromagnetic Spectrum is topic 34 of 115 in Atomic Structure & Periodicity.