What is absorption spectrum and emission spectrum? Give examples if you can!
An emission spectrum is the light emitted when an element in the gaseous state is heated. An absorption spectrum is the spectrum that is obtained when white light shines through a gaseous element.
Light that consists of all visible colours (“white light”) is called a continuous spectrum.
(from www.bbc.co.uk)
An emission spectrum is the light emitted when an element in the gaseous state is heated.
It is caused when the electrons in excited atoms drop to lower energy states and emit energy as light of specific colours.
Each type of element emits its own emission spectrum.
Here are some examples of emission spectra.
When white light passes through an element in the gaseous state, some of the energy is absorbed by the electrons in the atoms.
The electrons go into a higher energy state, and the light that passes through is missing the colours that correspond to the energies absorbed.
The spectra are called absorption spectra.
They consist of black lines against a coloured background.
from www.khanacademy.org)
The absorption and emission spectra are negatives of each other.
What is absorbed in the absorption spectrum of one element is emitted in the emission spectrum for that element.
The emission (and absorption) spectra are different for each element), so you can identify an element just by looking at its spectrum.
Here are some videos of flame tests which show the colors given off by atoms of different elements when they are heated.
Video from: Noel Pauller
Video from: Noel Pauller
