Why Do Different Metal Salts Produce Different Colors When Burned In A Flame?
If you put something in a flame, it will change color. Atoms are made up of positively charged nuclei around which negatively charged electrons move according to the rules of quantum mechanics. Quantum mechanics forces them to show up differently, called orbitals.
When electrons in an atom are left alone, they tend to settle into orbitals that give the atom the least amount of energy possible. This is called the atom's ground state. When you put metallic salts into a flame, the looser electrons farthest from the nucleus get more energy, pushing them into other orbitals. At some point, these excited electrons fall back to where they belong. When they do, they release the energy they have been holding onto as tiny particles of light called photons.
Flame Tests
Flame tests are helpful because when a gas is excited, it gives off a signature line emission spectrum. On the other hand, incandescence makes a continuous band of light whose peak depends on how hot the object is.
When heating or an electrical field energizes the atoms of a gas or vapor, their electrons can move from their ground state to higher energy levels. As they return to their ground state, they follow clearly defined paths based on quantum probabilities. As they do this, they give off photons with specific amounts of energy. This energy is the same as a particular wavelength of light, making an exceptionally light color
The color of a candle flame lets us know how hot it is. The center of a candle flame is light blue and about 1400 °C. That is where the flame is the most desirable. Inside the flame, the
color goes from yellow to orange to red. The temperature will drop as you move away from the center of the flame. The red part is about 800 °C or 1070 K.
The orange, yellow, and red in a flame have nothing to do with how hot the colors are. A big part of the color of a flame is also how excited the gas is. Soot, made up of many different kinds of carbon compounds, is one of the main parts of a flame. Because of these compounds' differences, electrons can be excited to a nearly endless number of quantum states. The color of the light depends on how much energy each electron gives off as it returns to its original state.
Energy of the Metallic Salts
The energy of the metallic salts that are given off determines the color of the light that is given off. The significance of the photons is determined by how much energy it takes to move electrons from one orbital to another. A flame always has many different kinds of power, and sometimes it gets lucky and has just the right amount to move an electron from one orbital to another. The electron must give off the same energy it took in when it falls back down.
Depending on what you put in the flame, different points of photons will show up as different colors. Each color is as unique to each element as a person's fingerprints are to them.
Place a small table salt in a flame for a simple experiment at home. You will see the same yellow glow from a sodium street light, except that an electric current instead of a flame moves the sodium electrons around. Due to the element boron, a little bit of boric acid, which you can get at a pharmacy, will make a beautiful green metallic salt flame.