Assertion (A): Radioactive decay is a nuclear process. Reason (R): It involves changes in the nucleus of an atom.
A. Both A and R are true but R is NOT the correct explanation of A.
B. A is false but R is true.
C. A is true but R is false.
D. Both A and R are true and R is the correct explanation of A.
Answer: Option D
Solution (By JKSSB Mock Tests)
Radioactive decay is a spontaneous process where an unstable atomic nucleus loses energy by emitting radiation. Since it involves the emission of particles (protons, neutrons, electrons) from the nucleus, it fundamentally alters the nucleus, making it a nuclear, not chemical, process.
Explanation:
Ozone (O₃) has one coordinate bond; a central oxygen donates a lone pair to another oxygen. CH₄, NH₃, H₂O have ordinary covalent bonds, though NH₃ can donate a pair to form NH₄⁺.
Explanation:
Carbon-14 is a radioactive isotope of carbon with a half-life of about 5,730 years. It is continuously formed in the atmosphere and incorporated into living organisms. When the organism dies, C-14 decays. By measuring the remaining C-14, scientists can determine the age of archaeological and geological samples up to ~50,000 years old.
Explanation:
In Fe₂O₃, oxygen has valency 2. Two Fe atoms combined with three O atoms: total negative charge = 6. For two Fe, total positive = 6, so each Fe has +3. Valency = 3 (ferric). In FeO, valency is 2 (ferrous).
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