Flame tests
There are several different tests to detect and identify the Electrically charged particle, formed when an atom or molecule gains or loses electrons. in A substance formed by the chemical union of two or more elements.. It is important that the test for any ion is unique and that the results of a test determine accurately which ion is present, rather than being uncertain about which ion it is.
Flame tests
Different Shiny element that is a good conductor of electricity and heat, and which forms basic oxides. ions produce different flame colours when they are heated strongly. This is the basis of flame tests. The steps of a flame test are:
- dip wire loop in hydrochloric acid to clean
- check that the wire loop is clean by holding in flame - if no colour is seen, the loop is clean
- dip a clean wire loop into a solid sample of the compound being tested
- put the loop into the edge of the blue flame from a Bunsen burner
- observe and record the flame colour produced
The table shows the flame test colours for five common metal ions.
| Ion present | Flame test colour |
| Lithium, Li+ | Bright red |
| Sodium, Na+ | Bright yellow |
| Potassium, K+ | Lilac |
| Calcium, Ca2+ | Orange-red |
| Copper, Cu2+ | Blue-green |
| Ion present | Lithium, Li+ |
|---|---|
| Flame test colour | Bright red |
| Ion present | Sodium, Na+ |
|---|---|
| Flame test colour | Bright yellow |
| Ion present | Potassium, K+ |
|---|---|
| Flame test colour | Lilac |
| Ion present | Calcium, Ca2+ |
|---|---|
| Flame test colour | Orange-red |
| Ion present | Copper, Cu2+ |
|---|---|
| Flame test colour | Blue-green |
Question
A sample of an An ionic compound occurs when a negative ion (an atom that has gained an electron) joins with a positive ion (an atom that has lost an electron). produces an orange-red flame test colour. Identify the metal ion present.
The metal ion is calcium, Ca2+.