Which elements have atoms that are likely to form an anion?
Select all that apply.
Hint: Review your periodic table.
phosphorus (P)
chlorine (Cl)
magnesium (Mg)
selenium (Se)
The Correct Answer and Explanation is :
To determine which of the elements listed are likely to form anions, we need to consider their positions on the periodic table and their tendency to gain electrons.
Elements Likely to Form Anions:
- Chlorine (Cl)
- Selenium (Se)
- Phosphorus (P)
Explanation:
- Chlorine (Cl):
- Chlorine is a halogen, located in Group 17 of the periodic table. Elements in this group have seven valence electrons and need only one additional electron to achieve a stable octet configuration. Consequently, chlorine readily gains one electron to form a chloride ion (Cl⁻). The tendency to gain an electron makes chlorine a strong candidate for anions.
- Selenium (Se):
- Selenium is a member of Group 16, which includes elements like oxygen and sulfur. Selenium has six valence electrons and similarly needs to gain two electrons to reach an octet. When it gains two electrons, it forms a selenide ion (Se²⁻). The ability of selenium to gain electrons makes it likely to form anions, although it is less reactive than chlorine.
- Phosphorus (P):
- Phosphorus is found in Group 15 and possesses five valence electrons. While phosphorus is more commonly known for forming covalent bonds, it can also gain three electrons to form a phosphide ion (P³⁻). Though it does not form anions as readily as chlorine or selenium, it is still capable of doing so under certain conditions.
- Magnesium (Mg):
- Magnesium is located in Group 2 and has two valence electrons. It typically loses these two electrons to achieve a stable configuration, resulting in the formation of a cation (Mg²⁺). Therefore, magnesium is not likely to form anions.
In summary, chlorine, selenium, and phosphorus are likely to form anions due to their positions on the periodic table and their electron configurations. Magnesium, on the other hand, tends to lose electrons and form cations rather than gaining them to form anions.