* Electronegativity: Chlorine has a high electronegativity, meaning it has a strong attraction for electrons. This is due to its small atomic radius and the strong pull of its positively charged nucleus on the outer shell electrons.
* Outer Shell: Chlorine has 7 electrons in its outermost shell. To achieve a stable electron configuration, it needs to gain one more electron to complete its octet (8 electrons in the outer shell). This stable configuration is like that of the noble gases, which are known for their inertness.
Therefore, by gaining an electron, chlorine fulfills the octet rule and reaches a more stable, lower energy state. This is why chlorine readily accepts an electron, making it a highly reactive element.
