Which of the following correctly compares the phosphorus isotopes [tex]${ }^{31}P$[/tex] and [tex]${ }^{32}P$[/tex]?

A. [tex][tex]${ }^{31}P$[/tex][/tex] has 16 neutrons, whereas [tex]${ }^{32}P$[/tex] has 17 neutrons.
B. [tex]${ }^{31}P$[/tex] has 31 protons, whereas [tex][tex]${ }^{32}P$[/tex][/tex] has 32 protons.
C. [tex]${ }^{31}P$[/tex] has 16 protons, whereas [tex]${ }^{32}P$[/tex] has 17 protons.
D. [tex][tex]${ }^{31}P$[/tex][/tex] has 31 neutrons, whereas [tex]${ }^{32}P$[/tex] has 32 neutrons.



Answer :

To compare the isotopes [tex]\( ^{31}P \)[/tex] and [tex]\( ^{32}P \)[/tex], let's analyze each component separately based on their mass numbers and atomic number:

1. Atomic Number of Phosphorus:
- The atomic number (Z) of phosphorus (P) is 15. This means that every phosphorus atom has 15 protons.

2. Mass Number:
- For [tex]\( ^{31}P \)[/tex], the mass number (A) is 31.
- For [tex]\( ^{32}P \)[/tex], the mass number (A) is 32.

3. Neutron Calculation:
- Neutrons are found by subtracting the number of protons from the mass number (A - Z).
- For [tex]\( ^{31}P \)[/tex]: [tex]\( 31 - 15 = 16 \)[/tex] neutrons.
- For [tex]\( ^{32}P \)[/tex]: [tex]\( 32 - 15 = 17 \)[/tex] neutrons.

With this detailed breakdown, we can now assess the given statements:

A. [tex]\(^{31}P\)[/tex] has 16 neutrons, whereas [tex]\(^{32}P\)[/tex] has 17 neutrons.
- This statement is correct. From our calculations, [tex]\(^{31}P\)[/tex] indeed has 16 neutrons and [tex]\(^{32}P\)[/tex] has 17 neutrons.

B. [tex]\(^{31}P\)[/tex] has 31 protons, whereas [tex]\(^{32}P\)[/tex] has 32 protons.
- This statement is incorrect. Both isotopes of phosphorus have 15 protons since the atomic number defines the number of protons, and it does not change with different isotopes.

C. [tex]\(^{31}P\)[/tex] has 16 protons, whereas [tex]\(^{32}P\)[/tex] has 17 protons.
- This statement is incorrect. Both isotopes of phosphorus have 15 protons.

D. [tex]\(^{31}P\)[/tex] has 31 neutrons, whereas [tex]\(^{32}P\)[/tex] has 32 neutrons.
- This statement is incorrect. Based on our calculations, [tex]\(^{31}P\)[/tex] has 16 neutrons and [tex]\(^{32}P\)[/tex] has 17 neutrons.

Thus, the correct answer is:
A. [tex]\(^{31}P\)[/tex] has 16 neutrons, whereas [tex]\(^{32}P\)[/tex] has 17 neutrons.