Question

The number of protons, electrons and neutrons in \(\text{P}^{3-}\) ion are, respectively

• A. \(15,15\) and \(16\).
• B. \(16,15\) and \(15\).
• C. \(15,18\) and \(16\).
• D. \(16,15\) and \(18\).

Hint:

Protons equal the atomic number, electrons are increased by the negative charge, and neutrons equal mass number minus atomic number.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
Phosphorus has atomic number \(Z=15\) and mass number \(A=31\).

Step 2: Protons and neutrons
Protons \(=Z=15\). Neutrons \(=A-Z=31-15=16\).

Step 3: Electrons
A neutral atom has \(15\) electrons. The ion \(\text{P}^{3-}\) gains \(3\) electrons, so electrons \(=15+3=18\).

Step 4: Compare the options
Protons, electrons and neutrons are \(15,18\) and \(16\), option (C).

Final Answer:
The ion has 15 protons, 18 electrons and 16 neutrons. \[ \boxed{\text{(C) }\text{15, 18 and 16}} \]