* They have 7 electrons in their outermost shell. This is what defines them as halogens.
* They are one electron short of a full outer shell. This makes them highly reactive, as they tend to gain an electron to achieve a stable octet configuration.
* They are highly electronegative. Their strong attraction for electrons makes them good oxidizing agents.
* They form ions with a -1 charge. This is because they readily gain an electron to fill their outer shell.
These characteristics are responsible for the unique reactivity and properties of halogens, making them important components in various chemical reactions and applications.
