Energy levels in atoms Flashcards
What are the properties of an atomic electron?
trapped by the electrostatic force of attraction of the nucleus
the energy of an electron in a shell is constant
an electron in a shell near the nucleus has less energy than an electron in a shell further away
What is the ground state and the excited state?
the lowest energy state of an atom
when one of the electrons moves to a shell at higher energy it is in a excited state
How does de-excitation occur?
the electron configuration in an excited atom is unstable because an electron that moves to an outer shell leaves a vacancy in the shell it moves from
the vacancy will be filled by an electron from an outer shell transferring to it
the atom moves to a lower energy level and a photon is emitted
What is the energy of the photon released equal to?
the energy lost by the electron and therefore the atom
hf = E1 - E2
When does excitation using photons occur?
the photon energy must be exactly equal to the difference between the final and initial energy levels of the atom
if the photons energy is different, it will not be absorbed
How does a fluorescent tube emit light?
contains a fluorescent coating
contains mercury vapour
ionisation and excition of atoms occur as they collide with electrons
atoms emit visible photons when they de excite
uv photons are absorbed by the atoms of the fluroescent coating
How can an element be detected using a line spectrum?
measuring the wavelength of a line spectrum
if the wavelength match it is of the same element
all spectrum are unique to that element
What causes a line in the line spectrum?
due to light of a certain colour/ wavelength
the photons that produce each line have the same energy
each photon is emitted when an atom de-excites
