Electrons occur in the outer parts of atoms, in orbitals corresponding to definite fixed energies. When an electron in an atom jumps from one particular orbital to another it gives rise to the emission or absorption of electromagnetic radiation at a specific characteristic wavelength. All chemical properties of atoms and molecules are determined by the electric interactions of electrons with each other and with the atomic nuclei.
The name "electron" was first suggested by G. Johnstone Stoney in 1891 for the natural unit of electricity. The particle that plays this role was discovered by J. J. Thomson in 1897. "Electron", "electricity", etc., derive from the term "electrica", coined by William Gilbert in 1600 to denote substances such as amber (electrum in Greek) that attract light objects when rubbed.
The wavelength of the electronUntil 1923 the electron was considered to be a particle only, but in that year Louis de Broglie proposed a new theory of the electron (see de Broglie and matter waves). De Broglie proposed that a moving particle, whatever its nature, has wave properties associated with it. The wavelength λ associated with any moving particle of mass m and velocity v, he proposed, is given by λ = h/mv where h is Planck's constant. The first experimental support for de Broglie's ideas came from the Davisson and Germer experiment. to
Related categories• ATOMIC AND NUCLEAR PHYSICS
• PARTICLE PHYSICS
• ELECTRICITY AND MAGNETISM
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