Answer:
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom. The electrons are filled according to Afbau's rule in order of increasing energies.
The last electron enters the third shell in all elements from Sodium to Argon.
Which are the followings and where is the data graphed i need a picture in order to help you
In chemistry, the octet rule explains how atoms of different elements combine to form molecules. In a chemical formula, the octet rule strongly governs the number of atoms for each element in a molecule; for example, calcium fluoride is CaF2 because two fluorine atoms and one calcium satisfy the rule. Hope this helps