U1 Topic 1 Electromagnetic Radiation & Atomic Spectra

Question 1

What is electromagnetic radiation?

Answer 1

Form of energy
Described as waves

Question 2

Different types of electromagnetic radiation will have …

Answer 2

Different wavelengths and frequencies

Question 3

what is the wavelength?

Answer 3

Distance between two adjacent crests of a wave.

Question 4

What is the frequency?

Answer 4

Number of waves to pass a fixed point per second. (sometimes measured in Hertz)

Question 5

If wavelength increases then the frequency must …… as the speed is ……

Answer 5

Decrease
Constant

Question 6

Radiation with a high frequency has?

Answer 6

A small wavelength

Question 7

Radiation with a low frequency has?

Answer 7

A large wavelength

Question 8

What is a photon?

Answer 8

when electromagnetic radiation interacts with matter there is a transfer of energy to the matter. Energy is transferred in small bundles called “quanta”.

Question 9

What does a photon carry?

Answer 9

quantised energy that is proportional to the frequency of radiation.

Question 10

What is planck’s constant?

Answer 10

Constant linking photon energy to frequency

Question 11

Photons in high frequency radiation can transfer greater amount of energy than what?

Answer 11

Photons in low frequency radiation

Question 12

What happens when a photon is absorbed?

Answer 12

Energy is gained by the electrons in a substance

Question 13

What happens when a photon is emitted?

Answer 13

Energy is lost by electrons in the substance

Question 14

What is avagrados constant?

Answer 14

Number of formula units present in one mole of a substance

Question 15

What happenes when energy is transferred to atoms?

Answer 15

Electrons within the atoms may be promoted to higher levels

Question 16

What happens to the promoted electron?

Answer 16

Becomes unstable and falls back down to the lower level. As this happens it emits a photon of light energy.

Question 17

If emitted energy falls within the visible spectrum what happens?

Answer 17

A colour will be observed

Question 18

What do some gaseous elements do when subjected to high voltages?

Answer 18

Emit light

Question 19

Light energy emitted by an atom can produce a spectrum which is made up of a series of lines at discrete energy levels. What does this prove?

Answer 19

The existence of energy levels

Question 20

The electrons that fall from different energy levels emit different energy why?

Answer 20

Because the energy levels are of a fixed energy

Question 21

Why can electrons which have fallen from high level to lower levels only have certain fixed frequencies (specific colours) ?

Answer 21

Because the energy levels are fixed.
The frequency and wavelengths of any radiation is determined by it’s energy

Question 22

Each element has characteristic what?

Answer 22

Absorption and emission spectrum which can be used to identify and quantify the elements

Question 23

The concentration of an element within a sample is related to?

Answer 23

the intensity of light emitted or absorbed.

Question 24

In emission spectroscopy what are high temperatures used for?

Answer 24

To excite the electrons within the atoms

Question 25

How is an emission spectrum produced?

Answer 25

By measuring the intensity of light emitted at different wavelengths.

Question 26

In absorption spectroscopy what is electromagnetic radiation directed at?

Answer 26

Atomised sample. Radiation is absorbed as electrons are promoted to higher energy levels.

Question 27

How is an absorption spectrum produced?

Answer 27

Measuring how the intensity of absorbed light varies with wavelength.