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Name:  Frank
Status:  educator
Age:  50s
Location: N/A
Country: N/A
Date: 2000-2001

Can you explain in some detail why different metal ions emit various colors in a flame tests??

Atoms have specific energy levels that their atoms can exist at. Different ions have different energy levels. When an material is heated, some of the electrons absorb energy. This pops them to higher energy levels. When an electron drops back down to a lower level, it releases the energy as radiation. When the energy is high enough, we see it as light. Blue is the highest energy visible light, while red is the lowest. Because each atom has its own energy levels, it can only release specific colors of light.


Metal ions at room temperature are almost exclusively in their lowest electronic state. When you heat the salt in a flame, the temperature is high enough to 1. Evaporate some of the salt and 2. There is enough heat energy to excite one or more (usually one) electron to a higher energy state. When these atoms de-excite the energy in the form of light is emitted. Every element has a characteristic fingerprint of emission lines depending upon its electronic state.

Vince Calder

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