Chapter 16, Problem 15STP

To determine

The number of neutrons from the periodic table.

Answer to Problem 15STP

With the help of mass number and atomic number.

Explanation of Solution

Introduction:

The number of neutrons can be calculated by identifying the atomic mass which is present at the bottom of the element in the periodic table and with the atomic number which is present on the top of the right of the element.Subtract the number of protons (atomic number) from the mass number to get the total number of neutrons.

Consider an example through which it getsclearer.

  ${}_{23}N{a}^{11}$

Here sodium is the element with the atomic number 11 atomic number at the top and mass number at the bottom. To find the number of the neutron. Subtract the atomic number from the mass number of the element.

  ${}_{23}N{a}^{11}=23-11=12$ neutrons.

Conclusion:The number of the neutronsin an element can be easily calculated from the periodic table.