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Examples of radioactive isotopes include carbon-14, tritium (hydrogen-3), chlorine-36, uranium-235, and uranium-238.
I'm pretty sure the answer is 1. I and III
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the amount of matter it contain
Answer:
For example, the atomic radius of the metal zirconium, Zr, (a period-5 transition element) is 155 pm (empirical value) and that of hafnium, Hf, (the corresponding period-6 element) is 159 pm. ... The increase in mass and the unchanged radii lead to a steep increase in density from 6.51 to 13.35 g/cm3.
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