Electromagnetic radiation and atomic spectra !!

Electrical magnetic radiation can be described in terms of ___________ and characterised in terms of _________?

• Waves

• Wavelength and/or Frequency

The relationship between wavelength and frequency is given by?

c = f × λ

The wavelength of visible light is usually expressed in?

Nanometres

Electromagnetic radiation can be described as a? And is said to have?

• As a wave and as a particle

• Dual nature

What is a photon?

When electromagnetic radiation is absorbed or emitted by matter it behaves like a stream of particles

What does a photon carry?

Quantised energy proportional to the frequency of the radiation

What happens when a photon is absorbed or emitted?

Energy is gained or lost by electrons within the substance

Energy is often in units of?

kJ mol ^‑1

When energy is transferred to atoms electrons within the atoms may be what?

Promoted to higher energy levels

An atom emits a photon of light energy when?

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

Atomic emission spectra are made up of what?

Lines at discrete frequencies

Each element in a sample produces?

Characteristic absorption and emission spectrum. These spectra can be used to identify and quantify the element.

In absorption spectroscopy, electromagnetic radiation is?

Directed at an atomised sample

Radiation is absorbed as?

Electrons are promoted to higher energy levels

How is an absorption spectrum produced?

By measuring how the intensity of absorbed light varies with wavelength

In emission spectroscopy higher temperatures are used to what?

Excite the electrons within atoms - as the electrons drop to lower energy levels, photons are emitted.

How is an emission spectrum of a sample produced?

By measuring the intensity of light emitted at different wavelength

In atomic spectroscopy , the concentration of an element within a sample is related to?

The intensity of light emitted or absorbed