Elements that typically form ions with a 1- charge are the halogens (Group 17) of the periodic table. These include:

* Fluorine (F)

* Chlorine (Cl)

* Bromine (Br)

* Iodine (I)

* Astatine (At)

These elements have seven valence electrons in their outermost shell. By gaining one electron, they achieve a stable octet configuration, which is a highly favorable state. This gain of an electron results in a 1- charge.

For example:

* Chlorine (Cl) has 7 valence electrons. It gains one electron to become Cl⁻, with 8 valence electrons, achieving a stable octet configuration.

Therefore, the halogens readily form ions with a 1- charge.