Because of the blue glass's color absorption capabilities, a potassium flame may be seen through cobalt glass. The yellow color created by sodium contamination in a sample is absorbed by cobalt glass, leaving only the purple light produced by potassium.
3 Explain why potassium is visible via the cobalt class. When potassium ions are burnt, they reach a higher energy state. When they cool, energy is released in the form of visible light with a distinct hue. The cobalt glass filters out yellow light, revealing the purple of the potassium ions.
Cobalt glass plates, like didymium glass, are used as an optical filter in flame tests to filter out the undesirable intense yellow light given by traces of sodium and enhance the ability to perceive violet and blue colours. The filters work because they pass only blue and violet light beyond 500 nm. This has no effect on visible light but it does affect the color balance of the beam being tested.
In industrial laboratories, where cost is not a concern, other types of glass can be used instead. For example, quartz glass will not absorb any significant amount of either sodium or potassium at wavelengths below about 400 nm so it would be suitable for use as a test tube for these elements. But since we are talking about flame tests here, what we need is a material that will not interfere with the color balance of the beam emitted by the source under investigation.
So even though didymium glass is less expensive than cobalt glass, it is still used as a filter in flame tests because it provides an adequate response to help distinguish between low levels of sodium and potassium in source samples.
The hue of the light is determined by the exact energy change that is occurring. Flame tests are a rapid way to produce the distinctive colors of metallic ions (we will talk more about ions later). In the flame of a lab burner, the loosely bound electrons of a metal are quickly activated. The activated electrons are now able to join together with other electrons to create compounds. This leaves the metal with fewer electrons than it started with and it becomes negative charged. A positive charge is called an ion. Therefore, metals are made up of negative ions.
Ions are present in all matter. They are responsible for many of the properties of materials. For example, the color of iron is due to its ability to absorb red and blue wavelengths of light but not green or yellow. This is because the iron atom has two extra electrons in its outer shell which cancel out any green or yellow wavelengths of light.
Ions also have a huge influence on our health. Some substances are toxic because they contain heavy metals. These metals are poisonous because their atoms have full shells with no electrons available to be shared. When metals lose electrons they become ions and these can be absorbed by other substances including humans. For example, copper is used in household wiring as it prevents oxidation and corrosion of wires. But if you are exposed to high levels of copper for long periods of time then it can be harmful. Too much copper in the body can lead to nerve damage and failure over time.
These unexpected hues are caused by the presence of certain metals in the burning substance... colors of other elements.
|K||Potassium||Light purple to red|
|Li||Lithium||Deep pink to dark red|
|Mn (II)||Manganese (II)||Yellow-green|
Calcium ions give the flame a brick red color and the glass it travels through a light green color. Calcium ions are imported into cells by calcium channels located on the cell membrane.
In biology, an ion is an atom or molecule that carries a net electric charge. In chemistry, an ion is any of various inorganic or organic chemical species having a net positive or negative charge. The term is also used for other charged particles such as electrons or muons. In physics, an ion is any particle that contains a net number of electrons. Ions play an important role in determining the physical properties of materials from which they are extracted. Ions are often classified by their mass. There are two main types of ions: cations (positively charged atoms or molecules) and anions (negatively charged atoms or molecules). Ions are involved in almost all aspects of life, from biological functions to human diseases. Ions are responsible for electrical conduction in metals, glass, and DNA. They are also key components in plasma screens, fluorescent lights, and sunscreens. Sulfate ions are one of the most common anions found in seawater. They contribute to the acidity of the water and help protect marine organisms from metal toxicity.
The electromagnetic spectrum depicts the visible light wavelengths and frequencies... Flame Testing Laboratory
|Metal Ion||Flame Color||Wavelength|
|Calcium, Ca2+||Deep Orange||500nm|
|Copper, Cu2+||Light Green||500nm|
|Potassium, K+||Pink & Purple||400nm|
|Strontium, Sr2+||Red Orange||700nm|
|Metals Used to Impart Color to Glass|