Beryllium-9 is a stable isotope of beryllium - Edexcel - GCSE Physics - Question 4 - 2013 - Paper 1
Question 4
Beryllium-9 is a stable isotope of beryllium.
(i) State the meaning of the term stable.
(ii) Beryllium-9 has an atomic number of 4 and a mass number of 9. A nucleu... show full transcript
Worked Solution & Example Answer:Beryllium-9 is a stable isotope of beryllium - Edexcel - GCSE Physics - Question 4 - 2013 - Paper 1
Step 1
State the meaning of the term stable.
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Answer
The term 'stable' means that the isotope does not emit (ionising) radiation; it is not radioactive. This implies that the nucleus remains intact and does not undergo radioactive decay.
Step 2
The number of neutrons in this nucleus is
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Answer
To determine the number of neutrons in beryllium-9, we subtract the atomic number (which is 4) from the mass number (which is 9):
Neutrons=MassNumber−AtomicNumber=9−4=5
Thus, the answer is B 5.
Step 3
Which one of these symbols describes the nucleus of a different isotope of beryllium?
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Answer
To identify the different isotope of beryllium, we must look for a symbol with a different mass number, while retaining the atomic number of 4. The answer would depend on the options presented as A, B, C, and D.
