Radioactivity or nuclear radiation is the process by which an unstable atomic nucleus loses energy by emitting radiation, such as an alpha particle, beta particle .Radioactivity was discovered in 1896 by the French scientist Henri Becquerel, while working with phosphorescent materials.
Radiation does not vary with chemical state.
In 1896, the French physicist Antoine Henri Becquerel accidentally found that a uranium-rich mineral called pitchblende emitted invisible, penetrating rays that could darken a photographic plate enclosed in an opaque envelope.
While working on phosphorescent materials, he happened to place the pitchblende on black paper that he had used to cover a piece of film. When he looked more carefully, he noticed that the film had lots of patches on it, and that this did not happen when other elements were placed on the paper. He eventually concluded that some rays must be coming out of the uranium crystals to produce this effect.
This means that rays carry energy, but pitchblende (a form of the mineral uraninite occurring in brown or black masses and containing radium ) emits them continuously without any energy input. This is an apparent violation of the law of conservation of energy. It was soon evident that Becquerel’s rays originated in the nuclei of the atoms.
The emission of these rays is called nuclear radioactivity, or simply radioactivity. The rays are called nuclear radiation. A nucleus that spontaneously destroys part of its mass to emit radiation is said to decay. A substance or object that emits nuclear radiation is said to be radioactive. Becquerel found radiation to be associated with certain elements, such as uranium.
Uranium is radioactive whether it is in the form of an element or compound. In addition, radiation does not vary with temperature, pressure, or ionization state of the uranium atom. Since all of these factors affect electrons in an atom, the radiation cannot come from electron transitions, as atomic spectra do.
Radiation does not vary with chemical state.
In 1896, the French physicist Antoine Henri Becquerel accidentally found that a uranium-rich mineral called pitchblende emitted invisible, penetrating rays that could darken a photographic plate enclosed in an opaque envelope.
While working on phosphorescent materials, he happened to place the pitchblende on black paper that he had used to cover a piece of film. When he looked more carefully, he noticed that the film had lots of patches on it, and that this did not happen when other elements were placed on the paper. He eventually concluded that some rays must be coming out of the uranium crystals to produce this effect.
This means that rays carry energy, but pitchblende (a form of the mineral uraninite occurring in brown or black masses and containing radium ) emits them continuously without any energy input. This is an apparent violation of the law of conservation of energy. It was soon evident that Becquerel’s rays originated in the nuclei of the atoms.
The emission of these rays is called nuclear radioactivity, or simply radioactivity. The rays are called nuclear radiation. A nucleus that spontaneously destroys part of its mass to emit radiation is said to decay. A substance or object that emits nuclear radiation is said to be radioactive. Becquerel found radiation to be associated with certain elements, such as uranium.
Uranium is radioactive whether it is in the form of an element or compound. In addition, radiation does not vary with temperature, pressure, or ionization state of the uranium atom. Since all of these factors affect electrons in an atom, the radiation cannot come from electron transitions, as atomic spectra do.
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