Final answer:
The halogens, elements in group 17 of the periodic table, always form 1- anions by gaining one electron to achieve a stable electron configuration.
Step-by-step explanation:
The name of the family of elements that always form 1- anions on the periodic table is known as halogens. Atoms of group 17 gain one electron to achieve the electron configuration of the next noble gas, thereby forming anions with a 1- 1 charge. Halogens include fluorine, chlorine, bromine, iodine, and astatine.
These elements are known for their high reactivity and are found in the next-to-last column of the periodic table. They form anions by gaining one electron, resulting in anions such as F- (fluoride), Cl- (chloride), Br- (bromide), and I- (iodide).