Name a metal ion that would produce a green flame.
How to approach this question
Recall the characteristic flame test colours for different metal ions. Think of a metal ion that gives a green or blue-green colour.
Full Answer
Copper / Barium
Several metal ions produce a green colour in a flame test. The most common one learned at GCSE is the copper(II) ion (Cu²⁺), which gives a blue-green flame. Another possible answer is the barium ion (Ba²⁺), which gives a pale green or apple-green flame and is also commonly used in fireworks.
Common mistakes
✗ Naming a metal that produces a different colour flame (e.g., sodium, potassium).
✗ Naming a non-metal.
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