Are you wondering, "Why is Helium right next to Hydrogen?" It is because such format explains the concept of Orbitals. Turns out, just like anything else, electrons and energy levels are not as simple as what meets the eye. Energy levels are divided into orbitals. Each orbital has a different shape, which tells you where you are most likely to find an electron at that certain energy point.
Trying to understand it may be hard at first, which is normal. We can first just learn what each orbital entails and have a basic understanding of each. There are four different types of orbitals which have different energy levels. S is the lowest, then P, then D, and finally the highest being F. The first energy level only has an S orbital; second has S and P; third has S, P, and D (we will explain this later in the next tab), etc.
o Can only hold 2 electrons
o Lowest energy orbital in each energy level
o Has a spherical shape
o Starts in the first energy level
o Can hold 8 electrons
o Second lowest energy orbital in each energy level
o Has the shape of a dumbbell
o Has three different orientation of shapes (if you want to learn why, research more on your own!)
o Can hold 10 electrons
o Second highest energy orbital in each energy level
o Has five different orientation/types of shapes (if you want to learn why, research more on your own!)
o Can only hold 14 electrons
o Highest energy orbital in each energy level
o Has seven different orientation/types of shapes