Choose the correct statements:
(A) Radioactive decay is the simplest example of a true first-order reaction. (B) It is customary to express the decomposition rate of radioactive material in terms of half-life. (C) Radioactive decay constant of an element varies significantly over wide environmental conditions. (D) SI unit of radioactivity is curie (Ci). (E) β-particles are actually electrons, and their ionizing power is much weaker than α\alphaα-particles.
Choose the correct answer from the options given below:

Correct option is C

1. Statement (A):
· Correct.
· Radioactive decay follows first-order kinetics, where the rate of decay is proportional to the number of undecayed nuclei. The rate equation is N=N0e−λt, which is characteristic of a first-order process.
2. Statement (B):
· Correct.
· The decomposition rate of radioactive materials is commonly expressed in terms of half-life (t1/2​), the time taken for half the nuclei to decay.
3. Statement (C):
· Incorrect.
· The radioactive decay constant (λ) is intrinsic to the isotope and remains constant, regardless of environmental conditions like temperature or pressure.
4. Statement (D):
· Incorrect.
· The SI unit of radioactivity is the becquerel (Bq), defined as one disintegration per second. The curie (Ci) is an older, non-SI unit, though still widely used in practice.
5. Statement (E):
· Correct.
· β-particles are high-energy electrons (or positrons). Their ionizing power is weaker than that of α\alphaα-particles because β-particles are less massive and carry a single charge compared to the doubly charged αparticles.
Thus, the correct statements are (A), (B), and (E).
Information Booster: 1. First-Order Kinetics in Radioactivity:
· Radioactive decay is independent of external conditions, a key feature of first-order reactions.
· Examples include uranium-238 and carbon-14 decay.
2. SI Unit of Radioactivity:
· Becquerel (Bq): 1 disintegration per second.
· Curie (Ci): Non-SI unit, where 1 Ci = 3.7×1010 disintegrations per second.
3. Ionizing Power of Particles:
· Α particles: Strong ionizing power, but low penetration.
· Β particles: Weaker ionizing power, higher penetration.
Additional Knowledge: (A) Radioactive Decay:
· Simplest example of a first-order process.
(B) Half-Life:
· Widely used to express the rate of decay.
(E) β Particles:
· Electrons or positrons emitted during beta decay.
(C) Decay Constant:
· Independent of environmental conditions.
(D) Unit of Radioactivity:
· Becquerel is the official SI unit.