Halogens tend to form anions because
A) losing electrons will make them attain a noble gas configuration faster than gaining them.
B) gaining electrons will make them attain a noble gas configuration faster than losing them.
C) halogen element ionization energies are lower than transition metal ionization energies.
D) halogen atomic radii tend to be larger than their corresponding ionic radii.
E) halogen atomic radii tend to be smaller than their corresponding ionic radii.
The Correct Answer and Explanation is:
Correct Answer: B) gaining electrons will make them attain a noble gas configuration faster than losing them.
Explanation:
Halogens, which include fluorine, chlorine, bromine, iodine, and astatine, are elements found in Group 17 (Group VIIA) of the periodic table. These elements are highly reactive nonmetals and are characterized by having seven electrons in their outermost electron shell (valence shell). Since the noble gases (Group 18) have eight valence electrons, halogens need only one more electron to achieve a full, stable octet configuration, similar to that of noble gases.
This drive for a full outer shell is the key reason halogens tend to gain electrons rather than lose them. By gaining one electron, a halogen atom transforms into a negatively charged ion, or anion (e.g., Cl⁻, Br⁻), reaching a stable noble gas configuration. This process is energetically favorable, meaning it usually releases energy (exothermic), because it leads to a more stable, lower-energy state.
On the other hand, if a halogen were to lose electrons, it would move further away from achieving the octet, making it highly unfavorable. For example, chlorine would have to lose seven electrons to reach the electron configuration of the previous noble gas (neon), which would require an enormous amount of energy—this is not a realistic pathway.
Additionally, halogens have high electronegativities and electron affinities, which means they have a strong tendency to attract and hold onto extra electrons. This further supports the idea that gaining an electron is more favorable than losing one.
Thus, Option B correctly identifies the fundamental reason halogens form anions: they gain electrons to achieve a noble gas configuration faster and more efficiently than by losing electrons.