Chlorine (Cl) belongs to Group 17 (Group VIIA) of the periodic table. The number of valence electrons and the valence shell of chlorine can be determined based on its position in the periodic table.
Chlorine has 7 valence electrons. Since it is in Group 17, it has 7 electrons in its outermost energy level (shell), which is also known as the valence shell. The electron configuration of chlorine is 2-8-7, with two electrons in the first energy level, eight electrons in the second energy level, and the remaining 7 electrons in the third energy level (valence shell).
The presence of 7 valence electrons in chlorine contributes to its high reactivity and tendency to gain one electron to achieve a stable octet configuration, forming the chloride ion (Cl-) in ionic compounds or participating in covalent bonding by sharing electrons with other atoms.