Atomic Spectroscopy Flashcards
(40 cards)
What spectrum does visible light belong too?
Electromagnetic radiation
What is an oscillation?
An oscillation is a wave like property that occurs in regular variations.
What is frequency?
Frequency is how many times the wave crests per second.
What is frequency measured in?
Hertz (Hz) with a unit of reciprocal seconds
What is a wavelength?
A wavelength is the distance between two crests of a oscillation. Wavelength is denoted by Lambda λ and is measured in meters.
What does the product of wavelength and frequency produce?
The speed of light (C (ms-1)).
If speed of light is constant in a vacuum, what does that imply about the relationship between wavelength and frequency?
That they are inversely proportional.
What is amplitude?
Amplitude is the displacement of the wave from the central point, therefor it is half of the total movement.
What property is amplitude responsible for in light?
It is responsible for the intensity of a light, not to be confused with energy of light. Higher amplitude = brighter light.
How do we calculate the energy of a wavelength?
To get the energy of a wavelength with multiply Planck’s constant (h) by the frequency of the wave (v) . E = h v
What is Planck’s constant and its unit?
Planck’s constant is 6.626 x 10-(34) and it is measured in Joules per second.
How do we get the unit of energy using E = h v?
If h is joules per second and frequency is measured in reciprocal seconds then we get E = Joules.
How does an increase of frequency appear on the electromagnetic spectrum?
An increase in frequency will correspond to a shorter wavelength and a higher energy. Higher frequency will move towards gamma rays, whilst lower frequency will move towards radio waves.
What is a broadband?
It is the collection of a range of frequencies. An example would be white light which is a collection of all visible light spectra.
What are the two possible effects that the absorption of energy can have on electrons?
Ionisation and Transition.
Ionisation is when a large enough energy can completely dissociate an electron from a nucleus. Transition is where a smaller energy is absorbed by the electron and it is transitioned into a higher state.
What is common in excited electrons?
These electrons will readily give up their excess energy so that they can fall back down to ground state.
How can an electron lose its excess energy?
It can either emit light (Fluorescence) or it can lose it in collisions to other molecules/atoms (Heat).
What is a fluorescent material?
It is a material that can absorb higher energy UV light and then re emit at a lower frequency which is the visible light.
How do we get an absorption spectrum?
We get it by subjecting a gas substance of interest with a full visible light broadband. The resulting black marks on a spectroscope determines the frequencies absorbed.
what is an emission spectrum?
It is when a gas discharge tube excites a gas of interest in a visible light absent environment. by passing the emitted light discharge through a prism we can determine the frequencies released.
Why is absorption and emission spectra useful?
Because each element has its own unique frequency characteristics which can then help with identification.
Why is the emission and absorption spectra of atoms quantised?
As the spectra can only have absolute specific values. This is because the electrons are restricted to specific energy states.
How many electrons can an orbital accomodate?
An orbital can either contain 0 , 1 or 2 Orbitals.
What does orbitals have to do with absorption and emission spectra?
Orbitals are the quantised energy levels that predefined how electrons get excited or emit. When an electron is excited it gets promoted to a higher orbital and vice versa.
