QUANTUM NUMBERS

~ describe one specific electron

~ 1st quantum number = PRINCIPAL QUANTUM NUMBER
            ~ abbreviated "n"
            ~ tells the energy level the electron is located in
            ~ n = number of the energy level
            ~ 1st energy level: n = 1, 4th energy level: n = 4, etc.

~ 2nd quantum number = ANGULAR MOMENTUM QUANTUM NUMBER
~ abbreviated " l "
~ tells the sublevel the electron is located in
~ tells shape of orbital
~ "s" sublevel:
l = 0, "p" sublevel: l = 1, "d" sublevel: l = 2, "f" sublevel: l = 3

~ 3rd quantum number = MAGNETIC QUANTUM NUMBER
~ abbreviated "m"
~ tells which orbital the electron is in
~ tells orientation of orbital around nucleus
~ m = -
l .. + l

~ 4th quantum number = SPIN QUANTUM NUMBER
~ abbreviated "
s "
~ tells which electron is being described
~ tells which way electron is spinning
~
s = -1/2 or +1/2

Pauli Exclusion Principle:

 

EXAMPLE QUESTIONS:
1.) What are the 4 quantum numbers for the following electron?
h
3 p

2.) If the electron in question 1 was the last electron added, what element would it be?

3.) Draw in the electron (and the orbital notation) for the electron with the following quantum numbers.
n = 3
l = 2 m = -1 s = -

4.) How many electrons in an atom can have the quantum numbers n = 3 and l = 1?

5.) What are the four quantum numbers for the electron circled in the diagram below?
n =
l = m = s =

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