Electromagnetic Spectrum

Question 1

what type of EM radiation has the highest energy?

Answer 1

Gamma Rays

Question 2

What type of EM radiation has the highest frequency / lowest wavelength

Answer 2

Gamma Rays

Question 3

What is wavelength?

Answer 3

The distance between wave crest to wave crest

Question 4

What is frequency

Answer 4

The number of waves per second

Question 5

What is the velocity of EM Radiation

Answer 5

The speed of light - 3x10^8 ms-1 ( the speed of the waves )

Question 6

what does the symbol _ mean?
v

Answer 6

Wavenumber - 1/ wavelength

Question 7

How can the energy of photons of radiation be calculated?

Answer 7

E = hf

Question 8

If the question asks you for the energy in kj mol -1 what equation should you use?

Answer 8

E = L x hf

Question 9

If a question asks you to calculate the wavelength of light corresponding to a bond energy, what should you use?

Answer 9

The bond enthalpy value given in the data booklet for that specific bond

Question 10

Is the energy associated with a photon of EM radiation proportional to the frequency?

Answer 10

Yes

Question 11

s the energy associated with a photon of EM radiation proportional to the wavelength?

Answer 11

No, it is inversely proportional

Question 12

When does an atom emit a photon of light energy?

Answer 12

When an excited electron moves from a higher energy level to a lower energy level. This energy releases a particular wavelength of light

Question 13

What is an excited atom?

Answer 13

An atom is excited when it has absorbed energy

Question 14

Describe emission spectra. ( long open ended questions )

Answer 14

-when energy is absorbed, electrons move up to an outer shell.
-energy in the form of a photon is released when electrons move to a lower energy level
-the energy is released as a particular wavelength of light
- differences between energy levels are fixed in any particular atom ( electrons at each level have fixed energy , energy of electrons are quantised )
- each wavelength / line on emission spectra is formed from a specific energy difference as electrons fall back to their excited state.
this allows various energy levels to be calculated from each wavelength obtained from an emission spectra.

Question 15

How can we excite atoms?

Answer 15

We can excite atoms by heating them with thew Bunsen burner, they then absorb this heat energy and the electrons use it to move up to a higher energy level.

Question 16

What is the ionisation energy

Answer 16

The energy difference between ground state and the confergence limit.

Question 17

What causes the separate lines on an emission spectrum?

Answer 17

Each electron transitions causes a separate line.

Question 18

As energy levels get further from the nucleus, what happens to the lines on an emission spectrum?

Answer 18

The lines get closer

Question 19

What are the black lines on an absorption spectrum?

Answer 19

The black lines show some missing wavelengths, this happens when an electron being promoted to a higher energy level as radiation is absorbed so will show black lines ( light is absorbed not reflected )

Question 20

What happens in atomic spectroscopy?

Answer 20

As the concentration of compound increases the intensity of radiation absorbed increases but the intensity transmitted radiation will decrease.