**Examples
for atomic physics**

Example #1

Problem:

a.) What is the
energy of a photon emitted as an electron moves from the * n*
= 5 to the

Solution:

The energy of each level goes as
(13.6 *eV*)/**n**^{2}. The
difference between the * n* = 5 and

energy of the photon's energy.

6.256
*eV*

b.) What is the wavelength of such a photon?

Solution:

Change the energy to Joules, then
use * E* =

199
*nm*

c.) What is the energy of a photon in the same transition is carbon (Z=6)?

Solution:

The energy scales as **Z**^{2},
so multiply the answer in part * a* by 36.

225*
eV*

Example #2

Problem:

a.) How many
electrons are in an atom specified by 1s^{2},2s^{2},2p^{6},3s^{2},3p^{4}?

Solution:

Count up the numbers in the superscripts.

16

b.) Write the spectroscopic notation for a neutral gold (Au) atom? See periodic table.

Solution:

See that a gold atom should have 79 electrons by looking at the periodic table. Then count up:

1s^{2},2s^{2},2p^{6},3s^{2},3p^{6},3d^{10},4s^{2},4p^{6},4d^{10},4f^{14},5s^{2},5p^{6},5d^{10},5f^{1}