Final answer:
A neutral chlorine atom possesses 17 electrons, matched to its atomic number. These electrons are arranged across shells and subshells, with seven in the outermost valence shell, making chlorine eager to gain one more electron to satisfy the octet rule.
Step-by-step explanation:
A neutral chlorine atom has a total of 17 electrons. The distribution of electrons in a chlorine atom occurs in shells and subshells based on the principles of atomic structure. With an atomic number of 17, chlorine has 17 protons in its nucleus, and to balance the positive charge of the protons, a neutral atom must also have 17 electrons. The arrangement of these electrons is as follows: 2 electrons in the 1s subshell, 2 in the 2s subshell, 6 in the 2p subshell, 2 in the 3s subshell, and 5 in the 3p subshell. This distribution gives chlorine an electron configuration of 1s²2s²2p⁶3s²3p⁵.
These 17 electrons are distributed across the atom's electron shells with the outermost shell, or valence shell, containing seven electrons. Chlorine only requires one more electron to achieve an octet and satisfy the octet rule in its valence shell. This tendency to gain an electron is often observed during the formation of ionic compounds, such as table salt, where chlorine gains an electron from a sodium atom.