Chapter SH, Problem 16.4APP

To determine

To calculate: Number of neutrons in an atom of phosphorus-31.

Answer to Problem 16.4APP

Percentage of neutrons is 16.

Explanation of Solution

Given:

Mass number = $31$

Formula used:

Mass number is given by,

  $\text{Mass number = number of protons + number of neutrons}$

Calculation:

Atomic number of phosphorus is 15. Therefore, number of protons = 15.

Number of neutrons is calculated as:

  $\begin{array}{l}\text{Mass number = number of protons + number of neutrons}\\ \text{31 = 15 + number of neutrons}\\ \text{number of neutrons = 31}-15=16\end{array}$

Conclusion:

Percentage of neutrons is 16.