EL2

Question 1

describe the electromagnetic spectrum

Answer 1

Question 2

atomic emission spectra

Answer 2

-electrons move to higher energy levels when they gain energy
- when they return to lower levels they release this energy as photons
-energy levels are fixed so the energy the photons released corresponds to the gaps
- E=hf
-the gaps between energy levels are unique to each element and also the pattern of lines observed on an emission spectra
-an element can be identified by comparing its atomic emission spectrum against a database of spectra for other elements

Question 3

emission and absorption similarities and differences

Answer 3

atomic emission spectra
-shows the energy emitted when electrons move from higher to lower energy levels
- colored lines on a black background
-the lines converge at higher frequencies
atomic absorption spectra
-shows the energy absorbed when electrons move from lower to higher energy levels
-black lines on a colored background
-the lines are at the same positions as the emission spectrum for the same element

Question 4

explain E=hv

Answer 4

When electrons move from higher to lower energy levels they release energy in the form of photons.
The energy of the photons is equal to the gap between the energy levels.

Question 5

frequency wavelength and speed relationship

Answer 5

c=LETTERA GRACA TIPO hv

Question 6

lithium

Answer 6

bright red

Question 7

Na sodium

Answer 7

yellow

Question 8

K potassium

Answer 8

lilac

Question 9

Ca calcium

Answer 9

brick red

Question 10

Ba barium

Answer 10

apple green

Question 11

Cu copper

Answer 11

blue green

Question 12

describe the flame test

Answer 12

• Dip a platinum or nichrome wire loop into hydrochloric acid to clean it
• Dip it into the solution to be tested
• Hold it in a hot flame
• Record the colour observed