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Which best describes radioactivity introduced in the chapter?
AGain of neutrons by a stable nucleus
BLoss of electrons from a stable atom
CSpontaneous emission of radiation by unstable nuclei
DHeat released when atoms combine to form bonds
Answer & Solution
Correct answer: C. Spontaneous emission of radiation by unstable nuclei
1. The chapter introduces radioactivity as a property of certain elements.
2. Their nuclei are unstable and spontaneously emit particles or rays.
3. This emission is called radioactivity.
4. So option A is correct.
_Source: Selina Concise Chemistry Class 8, Ch on Structure of Atom (Mistral OCR'd PDF), section on radioactivity_
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