Quantum Numbers cont'd

So in order to use this procedure with particular atoms we have to start with Hydrogen because we know that Hydrogen has 1 electron, which is in the n = 1 shell. So beginning with hydrogen:

Element: Hydrogen, # of electrons = 1

n = 1, l = 0, m_l = 0, m_s = +1/2 (or you could write n = 1, l = 0, m_l = 0, m_s = -1/2), but since there is only one electron you only write one of these two options.

Now as we go down and continue to add these numbers the number of electrons will coincide with each element. The next one being Helium because it has two electrons:

Element: Helium, # of electrons = 2

n = 1, l = 0, m_l = 0, m_s = +1/2

n = 1, l = 0, m_l = 0, m_s = -1/2

Then, you continue down the line:

Element: Li, # of electrons = 3

n = 1, l = 0, m_l = 0, m_s = +1/2

n = 1, l = 0, m_l = 0, m_s = -1/2

n = 2, l = 0, m_l = 0, m_s = +1/2

So basically you just list everything in order and for each electron you count them and put the atom by the # of electrons it has

So write the configurations for Oxygen