Absorption and Emission Spectra Quiz

Questions and Answers

What is light?

An electromagnetic wave

Describe how an absorption spectrum is formed.

Electrons in an atom occupy the ground state. When white light is shone through a gaseous form of an element, the electrons absorb photons of light of specific energy. These frequencies of photon of light are then missing in the spectrum produced, instead there are dark lines showing the frequencies absorbed.

Describe how an emission spectrum is formed.

Electrons that have been excited are unstable and fall back to their ground state. When they fall, they release energy in the form of packets of specific energy (photons). These photons have specific energy and thus a specific frequency, producing colored lines on a black spectrum.

What does the quantization of energy absorbed by electrons show?

That electrons can only occupy certain fixed energy levels. Signup and view all the answers

What is the relationship between the energy of a photon and an electron falling from one level to a lower one?

The energy of the photon is equal to the energy difference between the levels; it is a quantum of energy. Signup and view all the answers

Why are only certain frequencies of light absorbed?

Because the frequency of light corresponds to quantized energy levels. Signup and view all the answers

What is the convergence limit?

When the lines on a spectrum get closer together at higher frequencies until they merge at n = infinity. Signup and view all the answers

Why do lines on a spectrum converge?

Because the higher energy levels get closer together. Signup and view all the answers

What does the convergence limit in a spectrum of an element show?

The element's ionization energy using E = hf. Signup and view all the answers

How is an emission spectrum of hydrogen produced?

Passing an electric discharge through the gas. Signup and view all the answers

Why is the hydrogen spectrum the simplest?

Because hydrogen only has one electron. Signup and view all the answers

Which series of lines in the hydrogen emission spectrum fall within the visible region?

The Balmer series. Signup and view all the answers

What energy level do hydrogen electrons fall to produce lines in the Balmer series?

n = 2 (the second energy level). Signup and view all the answers

What transition in energy level of an electron of hydrogen produces a red line in the Balmer series?

n = 3 to n = 2. Signup and view all the answers

What transition in energy level of an electron of hydrogen produces a green line in the Balmer series?

n = 4 to n = 2. Signup and view all the answers

What transition in energy level of an electron of hydrogen produces a blue line in the Balmer series?

n = 5 to n = 2. Signup and view all the answers

What transition in energy level of an electron of hydrogen produces a violet line in the Balmer series?

n = 6 to n = 2. Signup and view all the answers

Where does the Lyman series fall in the electromagnetic spectrum?

The UV wavelengths. Signup and view all the answers

What energy level do hydrogen electrons fall to produce lines in the Lyman series?

n = 1 (the first / lowest energy level). Signup and view all the answers

How does the convergence limit in the Lyman series relate to the ionization energy of hydrogen?

The electron is excited from n = 1 to n = infinity at the convergence limit in the Lyman series. The frequency at the convergence limit is related to the energy (E = hf); at the convergence limit, ionization occurs and the energy needed is the ionization energy of hydrogen. Signup and view all the answers

How does the energy of a photon relate to its frequency?

E = hf. Signup and view all the answers

Between Wave one with a wavelength of 695nm and Wave two with a wavelength of 802nm, which wave has higher energy and why?

Wave one has a higher energy because it has a smaller wavelength and therefore a greater frequency, and E = hf. Signup and view all the answers

Study Notes

Light and Electromagnetic Waves

Light is defined as an electromagnetic wave.

Absorption Spectrum Formation

Electrons in an atom occupy ground states and absorb specific energy photons from white light.
Photons of certain frequencies are absorbed, resulting in dark lines in the produced spectrum, indicating missing frequencies.

Emission Spectrum Formation

Excited electrons release energy as they return to ground states, emitting photons with specific energies.
These emitted photons create colored lines on a dark background in the spectrum, corresponding to their frequencies.

Quantized Energy Levels

Electrons absorb and emit energy only in discrete amounts, demonstrating that they occupy fixed energy levels.

Photon Energy and Quantum

The energy of a photon released during an electron's transition equals the energy difference between the two levels and is termed a quantum of energy.

Frequency Absorption

Only certain frequencies of light are absorbed due to their correspondence with quantized energy levels of electrons.

Convergence Limit

The convergence limit occurs when spectral lines approach each other at higher frequencies, eventually merging at n = infinity.

Reason for Spectrum Convergence

Lines on a spectrum converge because higher energy levels come closer together as energy increases.

Ionisation Energy and Convergence Limit

The convergence limit indicates an element's ionisation energy, calculated using the equation E = hf.

Producing Hydrogen's Emission Spectrum

An electric discharge through gas gives rise to hydrogen's emission spectrum.

Simplicity of Hydrogen Spectrum

The hydrogen emission spectrum is the simplest due to having only one electron.

Visible Region: Balmer Series

The Balmer series consists of lines in the hydrogen emission spectrum that fall within the visible region of the electromagnetic spectrum.

Balmer Series Energy Level Transitions

Lines in the Balmer series are produced when hydrogen electrons transition to n = 2.
Specific transitions create different colors:
- Red: n = 3 to n = 2
- Green: n = 4 to n = 2
- Blue: n = 5 to n = 2
- Violet: n = 6 to n = 2

Lyman Series and Wavelengths

The Lyman series occurs in UV wavelengths, with transitions falling to n = 1.

Convergence Limit and Ionisation Energy in Lyman Series

Convergence in the Lyman series relates to hydrogen's ionisation energy, corresponding to the transition from n = 1 to n = infinity.

Energy-Frequency Relationship

The energy of a photon is directly proportional to its frequency, expressed by the equation E = hf.

Wave Energy Comparison

Wave one (695nm) has higher energy than wave two (802nm) due to its smaller wavelength, leading to a greater frequency, which is consistent with E = hf.

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Description

Test your knowledge on absorption and emission spectra with this flashcard quiz. Learn about the properties of light and how absorption spectra are formed. Perfect for students studying chemistry or physics!