Question

Which one of them is a radioisotope?
A. Cobalt – 60
B. Carbon – 14
C. Carbon – 12
D. All the above

Answer 1

Isotopes are two or more types of atoms with the same atomic number (number of protons in their nuclei) and periodic table position (and so belong to the same chemical element) but distinct nucleon numbers (mass numbers) owing to varying numbers of neutrons in their nuclei. While all isotopes of the same element have almost identical chemical characteristics, their atomic weights and physical attributes differ.

Complete answer:
A radionuclide is an unstable atom that contains too much nuclear energy. This extra energy can be released as gamma radiation from the nucleus, transferred to one of its electrons and released as a conversion electron, or utilised to build and emit a new particle from the nucleus. The radionuclide is said to decay radioactively throughout these processes. Because these emissions are strong enough to free an electron from another atom, they are classified as ionising radiation. The radioactive decay of a nuclide can create a stable nuclide or a new unstable radionuclide that can decay further.

Cobalt-60 is a radioactive cobalt isotope that has a half-life of 5.2713 years. Nuclear reactors create it artificially. Neutron activation of bulk samples of the monoisotopic and mononucleic cobalt isotope is required for deliberate industrial manufacture.Carbon-12 is the more prevalent of the two stable isotopes of carbon, accounting for 98.93 percent of the element carbon on Earth; its abundance is owing to the triple-alpha process, which creates it in stars.

Carbon-14, often known as radiocarbon, is a radioactive carbon isotope having 6 protons and 8 neutrons in its atomic nucleus. The radiocarbon dating method is based on its presence in organic materials. Carbon-12, which makes up 99 percent of all carbon on Earth, carbon-13, which makes up 1%, and carbon-14, which exists in tiny amounts, are the three naturally occurring isotopes of carbon.

Hence option A and B are correct.

Note: Nuclear reactors, cyclotrons, particle accelerators, and radionuclide generators create radionuclides either naturally or artificially. Around 730 radionuclides have half-lives greater than 60 minutes. There are 32 primordial radionuclides, meaning they were generated before the world was formed. At least 60 more radionuclides have been discovered in nature, either as daughters of primordial radionuclides or as radionuclides created naturally on Earth by cosmic radiation. Half-lives of more than 2400 radionuclides are shorter than 60 minutes. The majority of them are created intentionally and have extremely short half-lives.