Answer: [tex]1s^22s^22p^63s^23p^64s^2[/tex]
Explanation:
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 electronic configuration for element with atomic number 20 is Calcium and will have 20 electrons and is written as:
[tex]1s^22s^22p^63s^23p^64s^2[/tex]
