8 valence electrons means that the element is stable. When we hear stable, we know the group to look at! Noble gases all have 8 valence electrons making them stable and have a full octet.
Here are some:-
Krypton
Argon
Neon
Sodium, Salt, Gold, Platium
Explanation:
It is known that the maximum value of ml is equal to the vale of l. But the minimum value of n is as follows.
n = l + 1
where, n = principle quantum number
l = azimuthal quantum number
Values of n can be 1, 2, 3, 4 and so on. Whereas the values of l can be 0, 1, 2, 3, and so on.
Also, "m" is known as magnetic quantum number whose values can be equal to -l and +l.
So, when n = 1 then l = 0 and m = 0.
When n = 2 then l = 1 and values of m will be equal to -1, 0, +1. As it is given that the magnetic quantum number ml = -1. Hence, it is only possible when n = 2.
Thus, we can conclude that the smallest possible value of the principal quantum number n of the state is 2.