Why do molecules give broad bands instead of sharp lines?

• They contain no electrons
• They move too fast to absorb
• They vibrate and rotate too, smearing the energies

Why do free atoms absorb and emit only certain wavelengths?

• Electrons sit on fixed rungs, so only exact gap energies fit
• Atoms are too small to see other light
• The lamp blocks all other colours

In absorption you shine a lamp through free atoms, while in emission you heat the atoms and read their own glow.

Circle one:   True   False

Calcium readings fall when phosphate is present in a flame method. What is the fault and the fix?

• Ionisation interference; cool the flame
• Chemical interference; add a releasing agent or use a hotter source
• Dirty optics; polish the lens

Why must the hollow cathode lamp be built from the measured element?

• So its light matches the analyte rungs exactly
• So the lamp lasts longer
• So the flame stays lit

Why must the sample become free atoms before measurement?

• Free atoms are cheaper
• Only free atoms give the sharp signature lines
• Molecules clog the burner

A student runs a dissolved salt straight into the instrument and expects sharp atomic lines with no atomisation step.

Circle one:   True   False

Readings sag because analyte atoms ionise in a hot plasma instead of absorbing. Which fix fits?

• Add an easily ionised metal to push the balance back to atoms
• Switch to a molecular solvent
• Measure at a random wavelength