Elemental Spectra Flashcards
What is it called when all electrons are in their lowest possible energy levels?
This is known as ‘ground state’.
When atoms absorb energy (such as heat) what happens to the electrons? How long does this happen for?
When they recieve energy, electrons ‘jump’ up to the next electron shell (sometimes more than one shell). When the atoms are not in their lowest energy levels the atom is said to be in an ‘excited’ state. The electrons then release photons (light particles) as they drop down to their lowest shells. It takes approximately 1 millionth of a second between when the electrons jump up till they drop back down again.
This process is used to identify an unknown substance, and can be used in a flame test. By burning the element, we can compare the unique light it outputs to a chart of known elements, which will give us the identity of the element itself.
Describe the process of Emission Spectroscopy. What are we identifying?
Emission Spectroscopy is the process of identifying an element based on its’ outputted light combination. An element is heated and releases light, which is focussed through a lens into a prism. The prism seperates the individual colours and projects them to create a Line Emission Spectra (a black strip with varying vertical coloured stripes). As each element outputs different combinations of light, each element’s spectra is unique.
Describe the process of Atomic Absorption Spectroscopy (AAS). What are we identifying?
AAS is the process of determining the amount of a substance within a solution (how much of the substance is in the solution). This is done by measuring how much light produced from another instance is absorbed by the solution, when it is vaporised by a flame. The light left over is known as the Absorbance Value, and tells us what percentage of the solution is made up by the substance.
