Why Each Metal Produces a Different Colour
Part of Flame Tests — GCSE Chemistry
This how it works covers Why Each Metal Produces a Different Colour within Flame Tests for GCSE Chemistry. Revise Flame Tests in Chemical Analysis for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 5 of 13 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 5 of 13
Practice
20 questions
Recall
15 flashcards
⚙️ Why Each Metal Produces a Different Colour
The colours arise from electron transitions in the metal atoms. Here is the sequence:
- Absorption (excitation): Heat from the Bunsen flame gives energy to electrons in the metal atoms. The electrons absorb this energy and jump to a higher energy level.
- Emission: The excited electrons are unstable. They quickly fall back down to their original (ground state) energy level.
- Light released: When electrons fall back down, they release the absorbed energy as light. The wavelength (colour) of the light emitted corresponds exactly to the energy difference between the two levels.
- Element-specific: Each element has uniquely spaced electron energy levels. Therefore each element emits light of specific, characteristic wavelengths — a unique colour "fingerprint".
Lithium's electron energy gaps produce red light (longer wavelength, lower energy). Copper's energy gaps produce green/blue light (shorter wavelength, higher energy). Sodium's gaps produce intense yellow-orange — so intense that even tiny traces of sodium contamination can mask other colours, which is why the wire must be scrupulously cleaned.