Electromagnetic Radiation and Atomic Spectra Flashcards
What is the order of the electromagnetic spectrum with increasing wavelength?
Gamma rays X-rays Ultraviolet Visible Infrared Microwaves Radio waves
What is the order of the electromagnetic spectrum with increasing frequency and energy?
Radio waves Microwaves Infrared Visible Ultraviolet X-rays Gamma rays
What is the conversion of nm to m?
x10^-9
What is wavenumber?
The reciprocal of wavelength (1/λ).
How do lines on an atomic emission spectra arise?
An electron in ground state in a lower energy level absorbs energy and is promoted to a higher energy level (excited state). When the electron drops back down, energy is given out which corresponds to a line in the atomic emission spectra.
What do atomic emission spectra show?
Energy being given out by an atom or ion.
What does each line in an atomic emission spectra represent?
The difference in energy between the energy levels that the electron has moved between.
What units are wavelengths of light normally expressed in?
Nanometres (nm).
What are particles of electromagnetic radiation known as?
Photons.
What are atomic emission spectroscopy and atomic absorption spectroscopy used for?
To identify and quantify the elements present in a sample.
What formula is used to calculate the energy of light associated with a given wavelength?
E = Lhc/1000λ (wavelength should be in m)
Why might some elements/compounds not produce colours when placed in a Bunsen or subjected to a high voltage?
The energy supplied is not sufficient to promote electrons to an excited state or the light emitted is not in the visible region of the electromagnetic spectrum.
Why do emission spectra show up as a series of lines?
Several different electron transitions take place.
What term is given to the energy needed to promote an electron from energy level n=1 to infinity?
Ionisation energy.
What is the relationship between wavelength and frequency/energy?
Inversely proportional. Increase in wavelength means decrease in frequency/energy.
