radioactivity
18 questions tagged radioactivity — spanning every one of the seven Ws.
What is a half-life?
A half-life is the time it takes for half of the atoms in a radioactive sample to decay. It ranges from fractions of a second to billions of years.
Why are some elements radioactive?
Some elements are radioactive because their atomic nuclei are unstable and spontaneously break down into more stable forms. This happens when the balance of protons and neutrons cannot hold the nucleus together well enough.
Which element is the most radioactive naturally occurring element?
Polonium is often described as the most radioactive naturally occurring element because all its isotopes are highly unstable. Polonium-210 is especially famous for its intense alpha radiation.
Whose discovery revealed radioactivity as a natural phenomenon?
Henri Becquerel’s discovery in 1896. He found that uranium salts could fog photographic plates without sunlight.
Whose research on radioactivity earned two Nobel Prizes and transformed nuclear science?
Marie Curie’s research. She won Nobel Prizes in Physics in 1903 and Chemistry in 1911 for her work on radioactivity and radium.
Whose work discovered the element polonium?
Marie Curie and Pierre Curie discovered polonium in 1898. Marie Curie named it after her homeland, Poland.
Whose work discovered the element radium?
Marie Curie and Pierre Curie discovered radium in 1898. It became famous for its intense radioactivity and its early medical uses.
Whose experiments led to the discovery of radon?
Ernst Dorn discovered the radioactive gas radon in the early 20th century, building on work that identified it as a decay product of radium. Radon is now known as a noble gas and a health hazard in homes.
Whose work first separated uranium and its decay products into distinct radioactive elements?
Ernest Rutherford and Frederick Soddy developed the theory of radioactive decay in the early 1900s. Their work showed that one element can transform into another over time.
How does radioactive decay change one element into another?
Radioactive decay changes an unstable nucleus into a more stable one, often turning it into a different element. Alpha decay, beta decay, and gamma emission are the main types.
What is a radioactive isotope?
A radioactive isotope is an isotope with an unstable nucleus that decays over time by emitting radiation. Its decay rate is measured by its half-life.
Which force is responsible for the decay of the neutron into a proton?
The weak nuclear force is responsible for neutron beta decay. It changes a neutron into a proton while emitting an electron and an antineutrino.
Whose work led to the naming and discovery of radium and polonium?
Marie and Pierre Curie’s. They isolated radium and polonium from uranium ore and transformed the study of radioactivity.
How do radioactive isotopes decay?
Radioactive isotopes decay when unstable nuclei change into more stable ones by emitting particles or energy. Common modes include alpha decay, beta decay, and gamma emission.
Which force is responsible for alpha decay through quantum tunnelling?
The strong nuclear force helps trap alpha particles inside nuclei, while quantum tunnelling allows them to escape. The decay itself is governed by nuclear forces and quantum mechanics.
Whose discovery first identified radioactivity in uranium salts?
Henri Becquerel’s. In 1896, he found that uranium compounds emit penetrating radiation without needing sunlight.
Whose work isolated radium and polonium from pitchblende?
Marie and Pierre Curie’s. In 1898, they identified radium and polonium while studying the radioactivity of pitchblende.
How many elements are radioactive?
About 38 elements have no stable isotopes and are considered radioactive in all their forms. Several additional elements also have radioactive isotopes even if some stable ones exist.