Question fb. Why is the electromagnetic spectrum continuous? Why is the electromagnetic spectrum a transverse wave? Why are atomic spectra of an element discontinuous? Why is the electromagnetic spectrum important? Why do atomic spectra appear as lines? When the atoms of a gas or vapor are excited, for instance by heating or by applying an electrical field, their electrons are able to move from their ground state to higher energy levels.
As they return to their ground state, following clearly defined paths according to quantum probabilities, they emit photons of very specific energy. This energy corresponds to particular wavelengths of light, and so produces particular colors of light. Each element has a "fingerprint" in terms of its line emission spectrum, as illustrated by the examples below.
Because each element has an exactly defined line emission spectrum, scientists are able to identify them by the color of flame they produce. For example, copper produces a blue flame, lithium and strontium a red flame, calcium an orange flame, sodium a yellow flame, and barium a green flame. Any element placed in a flame will change its color. Atoms are made of positively charged nuclei, about which negatively charged electrons move according to the laws of quantum mechanics. Quantum mechanics constrains them to appear in various distinct patterns, called orbitals.
Orbitals are a lot like planetary orbits, but blurrier, so that you're never quite sure just where the electrons are. Left on their own, the electrons of an atom tend to relax into orbitals that leave the atom with the lowest possible energy--its ground state. Putting atoms into a flame, though, adds energy to the looser electrons farthest from the nucleus and pushes them into other orbitals. Eventually, these excited electrons drop back to where they ought to be, and in so doing, they release the energy they stored up as particles of light, called photons.
The color of the light emitted depends on the energies of the photons emitted, which are in turn are determined by the energies required to move electrons from one orbital to another.
Ben Davis February 8, What are colorful light emissions in everyday life? What is the emission of light? Which electrons are responsible for the emissions of colored lights? Why do chemicals have to be heated before colored light is emitted?
Why don t all heated substances give off colored light? Why do different chemicals emit different Colours of light? What color of light has the most energy? What color of light is lowest in energy? How did Bohr prove that an atom must exist?
What did Dalton get wrong? Why is Dalton credited? What 5 contributions did John Dalton make?
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