Hydrogen Emission Spectrum

What happens when gaseous hydrogen is subjected to high voltage at reduced pressure?

It emits light.

What happens to electrons when an atom absorbs energy?

They move from a lower energy level to a higher energy level.

What is an excited state?

An atom in which one or more electrons have absorbed energy and moved to a higher energy level.

What happens when an excited electron returns to a lower energy level?

A photon is emitted.

What determines the energy of the emitted photon?

The energy difference between the two electron energy levels.

Why does hydrogen produce a line emission spectrum rather than a continuous spectrum?

Electrons can only occupy specific quantized energy levels, so only specific photon energies and wavelengths can be emitted.

What does each line in a hydrogen emission spectrum represent?

A specific electron transition between two energy levels.

What does a spectral line indicate about the energy levels of hydrogen?

It represents the energy gap between two energy levels.

What is an emission line spectrum?

A spectrum consisting of specific, discrete wavelengths of light emitted by excited atoms.

What is a continuous spectrum?

An unbroken range of all wavelengths of visible light.

What is an absorption spectrum?

A spectrum produced when electrons absorb specific wavelengths of light and move to higher energy levels.

What is the difference between absorption and emission spectra?

Absorption involves electrons moving to higher energy levels; emission involves electrons moving to lower energy levels.

What is the relationship between frequency and energy?

Higher frequency corresponds to higher energy.

What is the relationship between wavelength and energy?

Higher energy corresponds to shorter wavelength; energy and wavelength are inversely related.

What is the relationship between frequency and wavelength?

Frequency and wavelength are inversely proportional.

What is frequency?

The number of wave cycles passing a point per second.

What is the unit of frequency?

Hertz (Hz), where 1 Hz = 1 cycle per second.

What is wavelength?

The distance between two corresponding points on a wave.

Which has higher energy: red or violet light?

Violet light.

Which has a longer wavelength: red or violet light?

Red light.

Which has a higher frequency: red or violet light?

Violet light.

Which has a shorter wavelength: red or violet light?

Violet light.

What type of photon is produced by a large energy gap?

A high-energy photon with a high frequency and short wavelength.

What type of photon is produced by a small energy gap?

A lower-energy photon with a lower frequency and longer wavelength.

Which region of the electromagnetic spectrum corresponds to the highest-energy hydrogen transitions?

Ultraviolet (UV).

Which region corresponds to lower-energy hydrogen transitions?

Infrared (IR).

What does the principal quantum number n represent?

The principal energy level occupied by an electron.

What does n = 1 represent?

The first principal energy level.

What does n = 2 represent?

The second principal energy level.

What does n = 3 represent?

The third principal energy level.

How do hydrogen energy levels change as n increases?

They become closer together and converge at higher energies.

Why do hydrogen spectral lines become closer together at higher frequencies?

The energy levels become increasingly close together as n increases.

What happens to the spacing between energy levels as n increases?

The spacing decreases.

What happens to the energy required to move between high energy levels?

The energy differences become smaller.

What is the Lyman series?

Hydrogen emission lines produced when electrons fall to n = 1.

Which region of the electromagnetic spectrum is the Lyman series found in?

Ultraviolet (UV).

What is the Balmer series?

Hydrogen emission lines produced when electrons fall to n = 2.

Which region is the Balmer series found in?

Visible light.

What is the Paschen series?

Hydrogen emission lines produced when electrons fall to n = 3.

Which region is the Paschen series found in?

Infrared (IR).

What is the Brackett series?

Hydrogen emission lines produced when electrons fall to n = 4.

Which region is the Brackett series found in?

Infrared (IR).

What is the Pfund series?

Hydrogen emission lines produced when electrons fall to n = 5.

Which region is the Pfund series found in?

Infrared (IR).

Why is the Balmer series visible?

The energy differences between higher levels and n = 2 correspond to visible-light photon energies.

Which energy level do electrons fall to in the Lyman series?

n = 1.

Which energy level do electrons fall to in the Balmer series?

n = 2.

Which energy level do electrons fall to in the Paschen series?

n = 3.

Which energy level do electrons fall to in the Brackett series?

n = 4.

Which energy level do electrons fall to in the Pfund series?

n = 5.

What type of transition produces an emission spectrum?

An electron moves from a higher energy level to a lower energy level.

What type of transition produces an absorption spectrum?

An electron moves from a lower energy level to a higher energy level.

What happens to energy during an emission transition?

The energy difference is released as a photon.

What happens to energy during an absorption transition?

Energy is absorbed as a photon.

How are photon energy and the energy gap between levels related?

They are equal.

Why are only certain wavelengths emitted by hydrogen?

Only specific energy-level transitions are possible, so only photons with specific energies and wavelengths are emitted.