FLAME TEST OF METAL CATIONS | EXPERIMENT 1

Flame test

A qualitative analytical technique where a sample of a metal ion is introduced into a flame and the emitted colour is observed.

Excited state (atom/ion)

• The state when an electron has absorbed energy and moved to a higher energy level.

Ground state

The lowest energy state of an atom/ion when electrons are in their lowest possible energy levels.

Ephoton​=hν; energy of a photon is Planck’s constant times its frequency.

Photon energy equation

c=λν; speed of light equals wavelength times frequency.

Wave-frequency relation

(blue)

Non-luminous ***** flame is preferred in flame tests because it gives clearer colours and fewer parasitic emissions.

overlapping

Not all metal ions produce visible flame colours; interference and *** colours; aqueous vs solid form difference.

Emission spectrum

When electrons drop to lower energy levels they *** photons at discrete wavelengths

high

Short wavelength → **** energy

low

Long wavelength → **** energy

blue-green

Cu²⁺ color

violet 

K⁺ color 

red/crimson

Li⁺ color

Yellow orange

Na⁺ color

red 

Ca²⁺ color

Continuous Spectrum

A spectrum that contains all wavelengths (and thus all colors) of visible light, uninterrupted, like that produced by sunlight.

Line Spectrum

A spectrum that shows only specific, discrete wavelengths of light, produced when excited atoms emit photons as their electrons fall back to lower energy levels.