How is the element's outer electron condition related to the position in the periodic table?

Hint: All elements are composed of subatomic particles of electrons and protons. The atomic number is the total number of protons present in the element. Generally in neutral atoms, the number of electrons and protons are usually the same. According to the atomic number the elements are placed in the modern periodic table.

Complete step by step answer:
The atom consists of electrons which are present inside the atoms in specific orbits or shells. These electrons are present in the shells according to the energy. The distribution of the electron is similar to how the planets move in our solar system.
The electrons are placed in shells according to the energy. These shells are also given naming convention which helps in the description of an electron that is present in the atomic shells.
All the electrons in the atom have some quantum numbers which are used to describe its location and thus also help in inferring the properties that the element is going to show.
The quantum numbers are namely the principal quantum number, the azimuthal quantum number, magnetic quantum number and the spin quantum number.
The principal quantum number shows the shell in which the electron is present and the azimuthal number shows the subshell. The magnetic quantum number shows the arrangement inside the subshell while the spin quantum number shows the spin.
The number of shells present in an element gives the period number and thus by the knowledge of the electronic configuration we can get the group number of an element in the periodic table.

Note: The atomic number of the atom is the total number of protons present in the nucleus of the atom. The total number of electrons is not a reliable measure for the atomic number as the number of electrons can vary as the atom tends to lose or gain electrons based on their bonding needs.
The modern periodic table is formed based on the plot of modern periodic law which states that the physical and chemical properties of the elements are a function of their atomic number.