Chapter 30, Problem 74A

To determine

To Explain:Results when the atomic number and mass number of a nucleus that emits a positron.

Answer to Problem 74A

When the nucleus emits a positron there is a change in the atomic number. Itdecreases by $1$ but there will be no change in the atomic mass number.

Explanation of Solution

Introduction:

Positron is also called as a positive electron. It is a positively charges subatomic particle which has the same mass and magnitude on the charge of an electron and also comprises of an electron with a negative charge.It is one of the types of radioactive decay methods and denoted by $\beta$ .

If the nucleus has a very less number of neutrons then a proton will change into a neutron and will transmit a positron that moves fast. It is called beta plus and the process is called positron emission.

When the nucleus emits a positron there is a change in the atomic number that is it decreases by $1$ but there is no change in the atomic mass number. Beta plus decay positron emission leads to the decrease in atomic number by $1$ , keeping the atomic mass number the same.

A positron is said to be the animator kind of an electron.The atomic mass number of positron is zero, but the relative charge of positron is $+1$ .

Conclusion:

When the nucleus emits a positron there is a change in the atomic number. It decreases by $1$ but there is no change in the atomic mass number.