1.2.1 - Bohr's Model of the Hydrogen Atom

Electromagnetic Radiation:

- Light travels…

→ in wavelengths

A —- is produced when…

→ a spectrum is produced when these waves of light are split through a prism.

The light is split because…

→ the different wavelengths of light that pass through a prism are refracted (bent) at different angles.

Visible light is…

→ only a tiny portion of the electromagnetic spectrum

Infrared light is…

→ less energetic than red light and has a longer wavelength.

Ultraviolet light is…

→ more energetic than violet light with a shorter wavelength

How is wavelength measured?

→ From the top of one troph to the other

Less energetic/less energy =

longer wavelength

More energetic/more energy =

shorter wavelength

Continuous Spectrum:

→ produced when white light is passed through a prism, the different colours merge together with no gaps.

Line Spectrum:

→ produced when a high voltage is applied to gas. Only discrete colours/wavelengths are produced with large separations where no light is produced (these appears as black).

Describe line spectrum in context to to electromagnetic radiation:

→ produced when atoms or molecules absorb or emit photons at specific wavelengths.

Evidence for Bohr Model of an atom:

→ atoms can emit light, wavelengths/different frequencies of light have different energies.

describe the process/what the atom has to do first to produce light:

→ they have to first absorb it then emit it

Emission Line Spectra:

→ An emission line spectrum is produced when electrons in an atom or molecule transition from higher energy states to lower energy states, releasing energy in the form of photons (particles of light).

→ They are unique to an element and only contain certain wavelengths/frequencies of light. This suggests that an atom can only have certain discrete separate quantities of energy.

Bohr’s Experiment on Atomic Scale Observations:

Under what conditions does the electron move to a higher energy level? Why is it moving?

→ When it comes really close to a UV photon

→ During this, the UV photon has transferred its energy to the electron, and now the photon has been absorbed by the electron, causing the electron to jump to a higher energy level.

Under what conditions does the electron move to a higher energy level? Why is it moving?

→ Higher energy level = ???

→ more energy for the electron

What happens when an electron moves to a lower energy level?

→ energy absorbed always has to be emitted

→ electrons always want to be in energy level number 1 (due to electromagnetic forces)

→ depending on the size of the jump, different amounts of energy will be emitted, releasing a different type of photon.

→ when the electron jumps down, it happens to release energy the shows a certain colour based on the size of the jump.

→ basically: energy being emitted = releasing different type of photon (depending on how much energy is being emitted)

Is there a pattern to which the electron is going up or down or both:

→ when it moves between energy levels, it absorbs and emits different colours (in form of UV photons)

→ UP depends on how much energy it absorbs

→ DOWN is more random as long as it goes to the bottom

What is the spectrometer indicating?

→ keeping track of all the emitted photons

Why are only certain colours being shown on the spectrometer? (connect this to atomic structure)

→ the amount of energy released depends on the size of gaps between the energy levels

Electromagnetic Spectrum:

Visible light has a higher or lower frequency than microwave?

→ Higher

red has a ____ frequency and purple has a ____ frequency

→ red has a low frequency and purple has a high frequency.

shorter wavelengths = —— frequency

longer wavelengths = —— frequency

→ shorter wavelengths = high frequency

→ longer wavelengths = low frequency

lines converge at ——- wavelengths (for the emission spectrum of hydrogen).

→ shorter