Question

in an argon emission spectrum would you expect to see a continuous spectrum or mostly black with few color lines

Answer 1

The emission spectrum would be mostly black with a few coloured lines. Here's why:

The coloured lines on an emission spectrum result from photons. These photons are produced when electrons in an atom of interest transition from a higher energy level to a lower energy level. This means the electron is losing some energy - and it's this energy that is transferred to the emitted photon.

If the difference between energy levels is small, the emitted photon will have a lower energy, so it's frequency will be lower and it's wavelength will be higher, and the light we see will appear closer to the red end of the spectrum.

If the difference between energy levels is large, the emitted photon will have a higher energy, so it's frequency will be higher and it's wavelength will be lower, and the light we see will appear closer to the violet end of the spectrum.

The reason why emission spectra only have a few coloured lines, instead of being continuous, is that electrons can only move between discrete energy levels, so the energy of the emitted photons can only take on a few discrete values. The absorption spectrum shows the opposite: it is a continuous spectrum with a few black lines, with the black lines corresponding to wavelengths of photons that are absorbed by an atom and cause an electron to transition from a lower energy level to a higher energy level.

Hope that makes sense! If you have any questions please ask!

Answer 2

So, all emission spectra consist of only a few colored lines?

Answer 3

Yup! The actual number of lines depends on the number of possible transitions between energy levels, which varies depending on the element we're talking about. Here are a few examples:

http://www.pas.rochester.edu/~afrank/A105/LectureVI/FG04_003_PCT.gif