Electrons and Energy Levels

Question 1

What is a Continuous Spectrum

Answer 1

A spectrum where all the values for an energy ( frequency or wavelength) are shown

Question 2

What is a Line Spectrum

Answer 2

A spectrum where only particular values are seen

Question 3

Explain how line spectras are produced

Answer 3

• Each spectral lines are at specific wavelengths
• Each spectral line corresponds to an electron falling down to a lower energy state
• Larger energy gap means higher energy photon is emitted so shorter wavelength

Question 4

Describe how the concept of energy levels is useful in the explanation of line spectra

Answer 4

• Only certain energies allowed
• A line corresponds to transition between levels each transition
• Each line corresponds to a definite wavelength [or frequency]

Question 5

Describe the Electron Energy Level Example Diagram

Answer 5

Question 6

What is the Ground State of an Atom

Answer 6

When electrons in an atom are in their lowest energy state so are closest to the nucleus

Question 7

Why are the energy levels negative

Answer 7

Because to become free, energy has to be supplied

Question 8

What is the Excitement of an Electron

Answer 8

When an electrons absorbs exactly the right amount of energy to move to a higher energy level

Question 9

When does the excitement of an electron occur

Answer 9

• Absorbing a photon with exactly the right amount of energy to move between levels
• Absorbing exactly the right amount of energy after colliding with a free electron that has enough energy to excite an electron

Question 10

What is the De-Excitement of an Electron

Answer 10

When an electron emits a photon of exactly the right amount of energy to move to a lower energy level

Question 11

What is Ionisation Energy

Answer 11

The minimum energy to remove an electron from the ground state

Question 12

Which way is emission and absorption in Energy Levels

Answer 12

Question 13

In energy levels which line has a bigger wavelength

Answer 13

The smaller the gap the bigger the wavelength

Question 14

Describe how a Fluorescent Tube works

Answer 14

• Free electrons collide with an electron from the atom (e.g mercury vapour)
• The electron from the atom is excited
• When either that electron or another electron will de-excite or return to the ground state it will emit a photon
• If the wavelength is visible then light is re emitted
• If the wavelength is not visible (e.g ultra violet) then it will collide with the electron from the phosphor coating
• The electron from the phosphor coating excites
• When the electron de-excites it produces a photon with wavelength that is visible and re emits light