A myriad of trends occur on the periodic table, whether it is defined through the size of the atoms or the first ionization energy that may occur, many other trends can be found simply looking horizontally or vertically on to the table. As you look from left to right you can see that the reactivity of the elements increase, this is due to the number of electrons increasing on the shell. This also once you go down the table; the shells become further and further apart from the nucleus so the bonding is a far weaker, the orbitals also increase when shells increase making the element more reactive than the previous compounds. The other trends that can be found when looking at the table is that the ionization energy is at its highest when looking at noble gases or hydrogen. This is due to their only being one electron in the structure of hydrogen, as well as their only being full outer shells in the compounds of the noble gases. You can only break these bonds with extremely powerful ionization energies which rarely occur due to it being far too dangerous to be using in everyday life. Other elements can be broken down quite easily; this is because of the electronegativity being relatively low. There can be other reasons for strong bonds (involving the orbitals) but in general there aren’t that many rules to follow. The sub-levels may determine slight changes in the ionization energy; however the same number of orbitals is present in each shell. There is a maximum number of electrons that are allowed to be present in each shell which is why it is then usually realized that the ionization of an element is inevitable.
Electrons in an atom exist in orbitals, this is due to the fact of the electrons being described by four different quantum numbers, this is shown through the principle quantum number which is; the main energy level. The second quantum number describes the type of orbital, called an s orbital. The second level