Collection of wavelengths can be emitted or absorbed by an Substance composed of atoms, each of which has the same atomic number (Z) and chemical properties. The chemical properties of an element are determined by the arrangement of the electrons in the various shells (specified by their quantum number) that surround the nucleus. In a neutral atom, the number of. Light is emitted by an atom when electrons change from a high energy state to a lower energy state, yielding an emission spectrum. Transfer of energy to a medium as a particle or electromagnetic radiation passes through it. Absorption of electromagnetic radiation is the combined result of Compton scattering, σ, and photoelectric absorption, τ. It may be quantified: where, t = thickness, ρ = density, and μ = mass absorption coefficient, which combines Compton and photoelectric effects (μ = σ + τ). of radiation can promote an electron to a higher energy level, yielding an Spectrum consisting of dark absorption lines superimposed over a continuum spectrum, created when a cooler gas absorbs photons from a hotter continuum source. The image shows the intricate dark Fraunhofer absorption lines superposed on the Sun’s background continuous spectrum. Dark Fraunhofer absorption lines superposed on the Sun's background continuous spectrum.. Each element has its own characteristic set of allowed energy states and allowed transitions between energy states are unique to a particular element.
Some or all content above used with permission from J. H. Wittke.