Quantum Numbers :
The set of quantum numbers are able to give us information about the position and energy of electrons present in an atom.
There are four quantum numbers –
The shape of a orbital is given by azimuthal quantum number.
Rules:
Question:
What set of quantum numbers describes the highest energy electron in the ground state of a nitrogen atom?
Heres the rule for mℓ again: start at negative ℓ, run by whole numbers to zero and then go to positive ℓ. Since ℓ = 1, we start with -1, go to zero and end up at +1. This gives us three values for mℓ when ℓ = 1. Hopefully you can see that, since ms takes on +½ and -½, we will wind up with six sets of quantum numbers.
Warning: theres going to be a new rule introduced after boron. So prepare yourself because, just as you thought it was getting easy, there gets added some new stuff. By the way, us mean old teachers didnt make all this stuff up to torture poor chemistry students. Nature really does do what I will explain below. Heres boron:
In each case, note that we start with the smallest value of n, ℓ, or mℓ possible. Make sure you look over the rules to see how each value was arrived at. ℓ starts at zero and goes to n – 1, which is zero since we get 1 – 1 = 0, when using n = 1. When ℓ = 0, there is only one possible choice for mℓ, which must be zero.
This “half-filled orbital” has definite chemical consequences. Remember it well. Also, using 2px first, then going to y and then z is purely convention. The x, y, z order is not of consequence in the above examples. However keep in mind the using each letter ONCE first being using it for the second electron is important.
n is ALWAYS the starting point for building up a series of quantum numbers. Each quantum number is then assigned according to a set of rules, each of which took years of study to finally determine. The rules ARE NOT just any old arbitrary ones; they have been determined from a study of nature. Remember the rules:
FAQ
What are the 4 quantum numbers?
What is the spin quantum number of nitrogen?
What are the 4 quantum numbers of oxygen?
Which one is the correct set of four quantum for 6th electron of nitrogen?
