# Is it possible to predict the color of the flame test result based on the element's structure?

The flame test is quite simple to do and very useful on the chemistry world, but to understand what your results mean you need to know previously a range variety of element-color relations. So, since the wavelength of the photon emitted reliess on the quantum jump done, I was wondering if, somehow, is it possible to make a fairly certain prediction of the results, based on the compound's structure. If someone knows a relation, it would be very useful.

• I find your question interesting, but the title seems slightly misleading. Correct me if I'm wrong, but the flame test is always only done on "metal elements" and never "compounds". So, isn't it incorrect to try predict the flame color based on a "compound's structure"? Maybe you meant an "element's atomic number" instead? – Gaurang Tandon Mar 10 '18 at 4:47
• It depends to what extent is given to your question. Methods exist that gives hints to even the vibrational spectrum of a molecule! But as you refer to flame test, its value (very high! ) is limited to didactics. The rest is spectroscopy. – Alchimista Mar 10 '18 at 10:01
• Exactly, you should look into infrared spectroscopy (en.wikipedia.org/wiki/Infrared_spectroscopy) and NMR spectroscopy (en.wikipedia.org/wiki/Nuclear_magnetic_resonance_spectroscopy), just to name two. – pentavalentcarbon Mar 10 '18 at 16:09
• @Gaurag Tandom, the flame test is most common and efficiently done in metals, especially when ionized, but it doesn't just aplly to those. Some uncommon non-metals like Phosporus or Boron are also usable. When i said "compounds structure" i meant the elements that are formed from the ionization process, but i appreciate you pointing the ambiguity on the question, i'll try to make it more precise! – Thunderlord Mar 10 '18 at 21:35

And then there is the problem with the actual jump. In a simple shell-model where you only add electrons in shells this jump is just to the next level. And you can introduce Rydberg-atoms and get element specific Rydberg-constants. But I remember to have tried that for a Lithium atom and if I didn't do a mistake back then it would have required quite a high energy level to get the red emission while in reality the principal quantum number (n) doesn't even change for lithium. You can see this pretty easily if you look at the energy diagram for the famous yellow sodium emission line. It's a jump from the $3p$ to the $3s$ orbital.