00:01
Hi there, we are writing a set of quantum numbers for each of the electrons where the principal quantum number is four in a selenium atom.
00:11
So the first thing i want to do is to write the ground state electron configuration for a selenium atom.
00:18
Selenium is atomic number 34, which means it has 34 protons and therefore 34 electrons.
00:27
So let's write its electron configuration.
00:29
Following the off -bough principle, we start with 1s, that's 1s2, that's 2s2, 2p6, 3s2, 3p6, 4s2, 3p6, 4s2, 3d10, and then 4p4.
00:56
Looking at where it's located, it's in the fourth group of the p block elements, so it's going to end with a p4.
01:03
I can double check my work by adding these electrons together.
01:07
4 .10, 12, 18, 20, 34.
01:11
All right, sure enough.
01:13
So we want to do electron configurations for the electrons when n equals 4.
01:19
So that means the 4s2 and the 4p4.
01:23
So let's start with the 4s2 electrons.
01:28
Remember, quantum numbers are a set of four numbers.
01:31
We have the principal quantum number, which is n, and that's the energy level.
01:36
So each of these electrons in 4s2 will have a principal quantum number of 4.
01:43
The next quantum number is the angular momentum quantum number.
01:47
That is the shape of the orbital.
01:50
S -shaped orbitals have an angular momentum quantum number of zero.
01:57
So each of these s electrons must be zero.
02:01
Next is the magnetic quantum number that refers to the orientation in space.
02:06
And it is an integer, and it ranges.
02:10
When we look at the angular momentum quantum number, the magnetic quantum number ranges from negative to positive of that value.
02:20
Well, zero is just zero.
02:23
So negative to positive means there's only one option, and that is zero.
02:27
And then the final quantum number is the spin quantum number...