Which of the following correctly compares the phosphorus isotopes 31p and 32p

A. 31p has 16 protons whereas 32p has 17 protons

B. 31p has 31 protons whereas 32p has 32 protons

C. 31p has 31 neutrons whereas 32p has 32 neutrons

D. 31p has 16 neutrons whereas 32p has 17 neutrons

APEX

D) 31p has 16 neutrons whereas 32p has 17

Explanation:

Apex Gang

The correct annswer is D) 31p has 16 neutrons whereas 32p has 17 neutrons

Explanation:

An isotope is an atom of an element with the same atomic number (Z) but a different mass number (A). That is, one isotope differs from another by the number of neutrons

Z = number of protons

A = number of protons + number of neutrons.

For the phosphorus example (P), whose Z = 15:

31P - > A = 31 = number of protons + number of neutrons

Z = 15 = number of protons

A = 31 = number of protons + number of neutrons - >

31 = 15 + number of neutrons - > number of neutrons = 31-15 = 16

In the case of 32P:

A = 32 = number of protons + number of neutrons

32 = 15 + number of neutrons - > number of neutrons = 32-15 = 17