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Figure 6 shows the mass number and the atomic number for the nuclei of five different atoms - AQA - GCSE Physics - Question 6 - 2021 - Paper 1
Question 6
Figure 6 shows the mass number and the atomic number for the nuclei of five different atoms. Figure 6 How many neutrons are there in a nucleus of atom A? Which ... show full transcript
Worked Solution & Example Answer:Figure 6 shows the mass number and the atomic number for the nuclei of five different atoms - AQA - GCSE Physics - Question 6 - 2021 - Paper 1
Step 1
Step 2
Step 3
Draw an arrow on Figure 7 to represent the alpha decay.
Answer
Alpha decay in Nucleus B results in a decrease of the mass number by 4 and the atomic number by 2. Draw an arrow from atom B (mass number 232, atomic number 86) moving to the atom with mass number 228 (232-4) and atomic number 84 (86-2), representing the new nucleus formed after alpha decay.
Step 4
What is meant by the ‘random nature of radioactive decay’?
Answer
The ‘random nature of radioactive decay’ refers to the unpredictability of when a particular nucleus will decay. While the average rate of decay (half-life) can be known for a sample, it is impossible to predict the exact moment when a specific nucleus will decay.
Step 5
Explain how these three decays result in a nucleus of the original element, polonium.
Answer
The decay process is as follows:
- A polonium (Po) nucleus emits an alpha particle, which reduces its atomic number by 2 and its mass number by 4, resulting in lead (Pb).
- The lead (Pb) nucleus then undergoes beta decay, where a neutron transforms into a proton, increasing the atomic number by 1 and keeping the mass number the same, resulting in bismuth (Bi).
- Finally, the bismuth (Bi) nucleus emits another beta particle, again transforming a neutron into a proton. This results in the atomic number increasing by 1, leading back to a polonium (Po) nucleus.
Thus, the sequence of decays ultimately leads back to a nucleus of polonium: