Absorption and emission spectrum Flashcards
What does an atomic emission spectrum look like
black background with coloured lines
What does an atomic absorption spectrum look like
coloured background with black lines
What is the equation that relates energy to frequency
E = hv
Define the terms in the equation E = hv and give units
E = energy (Joules)
h = plancks constant
v = frequency (hertz)
What is the equation that relates wavelength to frequency
C = λv
Define the terms in the equation C = λv and give units
C = speed of light (m/s)
λ = wavelength (m)
v = frequency (hertz)
Which way are electron moving to give lines on an emission spectra
from a higher energy level to a lower energy level
Why does each element have a unique emission spectra
each element has unique gaps between the energy levels
Why do the lines on an emission/absorption spectrum get closer together
as they get closer when frequency increases as the energy levels become closer together
Why are lined fixed on the spectrum
as electrons only exist in certain fixed energy levels and drops in levels gives out a specific amount of energy
What happens to electrons in spectroscopy
atoms that are given energy get excited and move into higher energy levels, they fall back down to a lower energy level giving out the energy as light (electromagnetic radiation)
Why are the lines in a atomic spectrum in sets
each set is a drop to a specific level
Electromagnetic spectrum
radio waves, infrared, visible light, ultraviolet, X-rays, gamma rays
radio -> gamma = decreasing wavelength, increasing frequency and energy
Explain the origin of the lines in an atomic emission spectrum
electrons in atoms can only be a certain fixed energy levels, atoms are given energy and electrons are promoted to a higher energy level, they fall back down to lower levels giving out the energy as electromagnetic radiation of frequencies given by (change in) E=hv, there are lots of different possible jumps each giving light of a different frequency and a different line on the spectrum
Diagram
Colour of lithium (flame test)
bright red
Colour of sodium (flame test)
yellow
Colour of potassium (flame test)
lilac
Colour of calcium (flame test)
brick red/orange
Colour of copper (flame test)
blue green
