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Why do different elements make different color flames when you burn them?

1 Answer

Answer:

Different elements have different flame colours because their electrons have different allowed energy levels.

Explanation:

The Bohr model says that electrons exist only at certain allowed energy levels.

When you heat an atom, some of its electrons are "excited* to higher energy levels.

When an electron drops from one level to a lower energy level, it emits a quantum of energy.

The wavelength (colour) of the light depends on the difference in the two energy levels.

We can see only those transitions that correspond to a visible wavelength.

In a hydrogen atom, for example, we can see only the transitions from higher levels to n = 2 (the Balmer series).

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Every element has its own characteristic set of energy levels.

Thus, an atom of Na has different energy levels and transitions than an atom of Li.

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The different mix of energy differences for each atom produces different colours.

Each metal gives a characteristic flame emission spectrum.

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Check out these videos of flame tests...

videos from: Noel Pauller