What is the most likely charge on an ion of phosphorus, P?
A) 5-
B) 3-
C) 3+
D) 5+
The Correct answer and Explanation is :
The most likely charge on an ion of phosphorus (P) is B) 3-.
Explanation:
Phosphorus is a non-metal found in group 15 (or group V) of the periodic table, and it has five valence electrons. The electron configuration of phosphorus is (1s^2 2s^2 2p^6 3s^2 3p^3). To achieve a stable electron configuration similar to the noble gas argon, phosphorus can either gain or lose electrons.
- Gaining Electrons (Anionic Form):
- When phosphorus gains three electrons, it achieves a stable octet configuration (8 electrons in its outer shell) by having a total of eight valence electrons (2 from the 3s subshell and 6 from the 3p subshell). The resulting ion is (P^{3-}), or phosphide. This anionic form is the most common and stable for phosphorus in many chemical compounds, especially in ionic compounds with metals.
- Losing Electrons (Cationic Forms):
- Phosphorus can also lose electrons, resulting in a positive charge. If it loses three electrons, it forms (P^{3+}), and if it loses all five valence electrons, it forms (P^{5+}). However, these cationic forms are less stable and less common compared to the anionic form. The energy required to remove electrons from phosphorus increases significantly with each subsequent electron removed, making (P^{3+}) and (P^{5+}) less favorable.
- Common Compounds:
- In nature, phosphorus predominantly exists in the form of (P^{3-}) in compounds like phosphides and phosphates. These compounds are essential for biological processes, such as the formation of DNA and ATP.
In summary, while phosphorus can exist in multiple oxidation states, the most stable and common ion is (P^{3-}), resulting from the gain of three electrons to achieve a full outer shell.