Problem
Question 5 An alpha particle is emitted from a radionuclide. What happens to the subsequent nucleon and atomic number number of the new isotope.. A Nucleon number reduces by 4 and the atomic number reduces by 2 B Nucleon number increases by 2 and the atomic number reduces by 4 C Nucleon number reduces by 4 and the atomic number reduces by 4 D Nucleon number reduces by 2 and the atomic number reduces by 2
Solution
Step 1 ：An alpha particle consists of 2 protons and 2 neutrons. When a radionuclide emits an alpha particle, it loses these 2 protons and 2 neutrons. This means that the nucleon number (the total number of protons and neutrons) of the radionuclide decreases by 4 and the atomic number (the number of protons) decreases by 2.
Step 2 ：Therefore, the correct answer is A: Nucleon number reduces by 4 and the atomic number reduces by 2.
Step 3 ：Final Answer: \(\boxed{\text{A: Nucleon number reduces by 4 and the atomic number reduces by 2}}\)
