Electronic configurations and a lot more.

So today were gonna focus on electrons.
So in my last class I asked you why electrons revolve around the nucleus. Got the answer? Well I'm not telling you.
Electrons revolve around the nucleus in fixed paths called shells or orbits. The shells they revolve in are determined by the "power" of electrons.
There are four shells that are required for you. These shells are given names.
The first shell is called shell "K"
The second "L"
The third "M"
The forth "N"
The capacity of these shells is determined by a rule. The 2n^2 rule.
N is the number of the shell.
So the first shell has the capacity of 2 electrons.
Find the rest on your own using 2n^2 rule only then continue.

So lets talk about electronic configurations now.
The shells are arranged in the order k  l  m  n.
So you just have to memorise the atomic numbers. I have given the elements till 20.
1) Hydrogen
2) Helium
3) Lithium
4) Beryllium
5) Boron
6) Carbon
7) Nitrogen
8) Oxygen
9) Fluorine
10) Neon
11) Sodium
12) Magnesium
13) Aluminium
14) Silicon
15) Phosphorous
16) Sulphur
17) Chloride
18) Argon
19) Potassium
20) Calcium

You have to memorise all these. Truthfully or learning chemistry is a waste.
So for the electronic configuration you just fill up the number of  electrons in the shells according to their capacity and the atomic number also you have to mention the number of protons and neutrons in the nucleus I have given a table here. Here is an
Example in the picture.
So you guys try yourself to make the configurations of all the elements till 20.
Ok so that's todays class.
P.S round off the atomic weights ok?