Answer:
1s² 2s² 2p⁶ 3s² 3p⁵
Explanation:
A neutral atom is an atom that has the same amount of protons and electrons, so its total charge is 0. The atomic number represents the number of protons, so, in a neutral atom, the number of electrons is equal to the atomic number.
The electron configuration is the representation of the number of electrons in each level and sublevel, in order of increase of energy. The levels are represented by a number (1 to 7), and the sublevels by letters (s, p, d, f, g...). The increase of energy is determined by the Linus Pauling diagram, as shown below.
The sublevel "s" can have at least 2 electrons, the sublevel "p" can have at least 6 electrons, the sublevel "d" can have at least 10 electrons, and the sublevel "f" can have at least 14 electrons. Thus, for the neutral atom of chlorine, with 17 electrons, the electronic configuration is:
1s² 2s² 2p⁶ 3s² 3p⁵