Define the ground state .

The ground state is the lowest energy level normally occupied by an electron in an atom.

Excitation is the process in which an electron gains energy and moves up to a higher energy level, becoming an excited state electron.

Ionisation occurs when an electron gains enough energy to be removed from the atom entirely.

State three ways an electron can absorb energy in order to move to a higher energy level.

Collisions with other atoms or electrons Absorbing a photon A physical source, such as heat

What happens when an electron returns to a lower energy level from a higher, excited state?

It releases energy in the form of a photon .

True or False? Electrons in an atom can have any value of energy.

False. Electrons in an atom can only have certain specific, discrete energies, called electron energy levels.

Define line spectra .

Line spectra are a series of coloured lines with dark spaces in between, produced when excited atoms emit light of certain wavelengths.

Why can elements be identified using their line spectrum?

Each element produces a unique set of spectral lines — no two elements emit the same set.

Define an emission spectrum .

An emission spectrum is a set of discrete wavelengths, seen as coloured lines on a black background, produced when electrons transition from a higher to a lower energy level, emitting photons.

Define an absorption spectrum .

An absorption spectrum is a continuous spectrum with dark lines at certain wavelengths, produced when a cool, low-pressure gas absorbs certain wavelengths from white light passing through it.

Why do certain wavelengths appear to be missing from an absorption spectrum, rather than simply absent?

Absorbed photons are re-emitted as electrons return to lower energy levels, but in all directions rather than the original direction of the white light, so those wavelengths appear missing from the transmitted beam.

The wavelengths missing from an absorption spectrum are the .......... as their corresponding emission spectrum of the same element.

The wavelengths missing from an absorption spectrum are the same as their corresponding emission spectrum of the same element.

True or False? An absorption spectrum is produced by passing white light through a hot, high-pressure gas.

False. An absorption spectrum is produced by passing white light through a cool, low-pressure gas.

In the equation Δ E = E 2 − E 1 , which energy level is E 1 and which is E 2 ?

E 1 is the energy of the lower level; E 2 is the energy of the higher level.

How do you convert an energy value from eV into joules?

Multiply the value in eV by 1.6 × 10 -19 .

The difference between two energy levels is equal to a specific .......... energy.

The difference between two energy levels is equal to a specific photon energy.

True or False? The largest energy change between two levels corresponds to the longest wavelength of radiation emitted.

False. Wavelength and photon energy are inversely proportional, so the largest energy change corresponds to the shortest wavelength.

A LevelPhysicsCambridge (CIE)Flashcards22. Quantum PhysicsEnergy Levels in Atoms & Line Spectra

Energy Levels in Atoms & Line Spectra (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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FrontAtomic Energy Levels
Define the ground state.

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Cards in this collection (20)

Define the ground state.
The ground state is the lowest energy level normally occupied by an electron in an atom.
Define excitation.
Excitation is the process in which an electron gains energy and moves up to a higher energy level, becoming an excited state electron.
Define ionisation.
Ionisation occurs when an electron gains enough energy to be removed from the atom entirely.
State three ways an electron can absorb energy in order to move to a higher energy level.
- Collisions with other atoms or electrons
- Absorbing a photon
- A physical source, such as heat
What happens when an electron returns to a lower energy level from a higher, excited state?
It releases energy in the form of a photon.
True or False?
Electrons in an atom can have any value of energy.
False.
Electrons in an atom can only have certain specific, discrete energies, called electron energy levels.
Define line spectra.
Line spectra are a series of coloured lines with dark spaces in between, produced when excited atoms emit light of certain wavelengths.
Why can elements be identified using their line spectrum?
Each element produces a unique set of spectral lines — no two elements emit the same set.
Define an emission spectrum.
An emission spectrum is a set of discrete wavelengths, seen as coloured lines on a black background, produced when electrons transition from a higher to a lower energy level, emitting photons.
Define an absorption spectrum.
An absorption spectrum is a continuous spectrum with dark lines at certain wavelengths, produced when a cool, low-pressure gas absorbs certain wavelengths from white light passing through it.
State the equation relating the energy change ΔE of an electron transition to the wavelength λ of the photon emitted or absorbed.
$Δ E = h f = \frac{h c}{λ}$
Why do certain wavelengths appear to be missing from an absorption spectrum, rather than simply absent?
Absorbed photons are re-emitted as electrons return to lower energy levels, but in all directions rather than the original direction of the white light, so those wavelengths appear missing from the transmitted beam.
The wavelengths missing from an absorption spectrum are the .......... as their corresponding emission spectrum of the same element.
The wavelengths missing from an absorption spectrum are the same as their corresponding emission spectrum of the same element.
True or False?
An absorption spectrum is produced by passing white light through a hot, high-pressure gas.
False.
An absorption spectrum is produced by passing white light through a cool, low-pressure gas.
State the equation linking the energy difference ΔE between two energy levels to the frequency f of the photon involved.
$Δ E = h f = E_{2} - E_{1}$
State the equation linking the wavelength λ of emitted or absorbed radiation to the energy difference between two levels.
$λ = \frac{h c}{E_{2} - E_{1}}$
In the equation ΔE = E₂ − E₁, which energy level is E₁ and which is E₂?
E₁ is the energy of the lower level; E₂ is the energy of the higher level.
How do you convert an energy value from eV into joules?
Multiply the value in eV by 1.6 × 10^-19.
The difference between two energy levels is equal to a specific .......... energy.
The difference between two energy levels is equal to a specific photon energy.
True or False?
The largest energy change between two levels corresponds to the longest wavelength of radiation emitted.
False.
Wavelength and photon energy are inversely proportional, so the largest energy change corresponds to the shortest wavelength.

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