The diagram shows the beta decay of carbon-14. What is the proton number of the daughter nucleus?
Question 1 Report
The diagram shows the beta decay of carbon-14.
What is the proton number of the daughter nucleus?
Answer Details
In beta decay, a neutron inside the nucleus converts into a proton, and the nucleus emits a high-speed electron (the beta particle). The mass number does not change because the total number of nucleons (protons + neutrons) stays the same: one neutron is lost but one proton is gained. However, the proton number increases by 1.
Carbon-14 has 6 protons and 8 neutrons. After beta decay, one neutron becomes a proton, so the daughter nucleus has 7 protons and 7 neutrons. The mass number remains 14. The element with proton number 7 is nitrogen, so the daughter is nitrogen-14.
A proton number of 5 would mean a proton was lost, which does not occur in beta decay. A proton number of 8 would mean two protons were gained. A proton number of 6 would mean no change at all. In beta decay, exactly one neutron transforms into one proton, so the proton number always increases by exactly one.
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