ionization

level

level 4

level 3

level 2

level 1

(ground

state)

A Electron

cannot

accept

5ek

Electron

cannot

accept

11 eV

A

Exactly

10.2 eV

allows

electron

to rise

to level 2

This electron

gains enough

energy to

escape the

atom

nm (nanometer) 1 nm - 10 m

frequency unit 1 Hz=1 s¹

Dropping from

level 2 to

level 1 requires

electron to

give up 10.2 el

Constants you may need:

Speed of light: 3 x 10³ m/s

Planck constant: h=4.1×10-¹5 eV x H₂¹

13.6 eV

12.8 eV

12.1 V

If an electron drops from energy level 3 to level 1.

a) How much energy does it lose (in units of eV)?

Show your calculation. (2 pts)

O eV

b) The loss of energy is carried away by an emitted

photon. What is the frequency of the photon? Show

your calculation. (2 pts)

10.2 eV c) What is the wavelength of the emitted photon in

nanometers (nm)? Show your calculation. (2 pts)

d) Is the wavelength in the visible light range? If

not, what kind of light is it? (2 pts)

e) What is needed for an electron to transit from

energy level 1 to level 3? Is it associated with an

emission line or absorption line? (2 pts)

Optional question (1 extra point to the total course score): Generally speaking, under what condition

does liquid methane exist? Where does liquid methane naturally exist in the solar system? How did we

find out there is liquid methane there?