Phosphorous can form an ion called phosphide, which has the formula P3−.
This ion __.
A. contains 18 electrons
B. forms when a phosphorus atom loses three protons
C. has properties very similar of P
D. is called a cation
The Correct Answer and Explanation is :
The correct answer is A. contains 18 electrons.
Explanation:
Phosphorus is an element found in group 15 of the periodic table, with an atomic number of 15. This means a neutral phosphorus atom has 15 protons and, consequently, 15 electrons. When phosphorus forms the phosphide ion (P³⁻), it gains three additional electrons, leading to a total of 18 electrons (15 original electrons + 3 additional electrons).
Option B is incorrect because the phosphide ion does not form by the loss of protons. In fact, gaining electrons increases the negative charge of the atom. The number of protons in the nucleus, which defines the element as phosphorus, remains unchanged at 15.
Option C is misleading; while phosphide may have some similarities to phosphorus, particularly in the context of being composed of the same element, the properties of phosphide are significantly different from those of elemental phosphorus. Phosphide ions are more stable and less reactive compared to elemental phosphorus, which can exist in several allotropes and tends to be quite reactive.
Option D is incorrect as well, since a cation is a positively charged ion formed by the loss of electrons. The phosphide ion (P³⁻) is an anion due to its negative charge, as it has gained electrons rather than lost them.
In summary, the phosphide ion (P³⁻) contains 18 electrons due to the addition of three electrons to a neutral phosphorus atom. This characteristic distinguishes it from the elemental form of phosphorus and highlights its role in chemical reactions and bonding.