what is a radioactive element? what can be said about the nucleus of the radioactive element?

Answer 1

A radioactive element is a naturally occuring or man made element whose nucleus is unstable and achieves stability by emission of either particulate radiation such as alpha and beta particles and or electromagentic radiation labeled as gamma rays. In greek alphabet, alpha corresponds to a, beta to b and gamma to c of of english alphabet. Alpha particle is a nucleus of Helium and contains 2 protons and 2 neutrons. Beta particles are electrons from the nucleus and are emitted when a neutron emits a beta particle and becomes a proton.

The nucleus changes its atomic number and atomic mass when alpha particles are emitted. It changes the atomic number without a change in the mass when a beta is emitted and it does not change the atomic number or mass number when gamma rays are emitted.

The new element of a radioactive decay may also be radioactive and may decay further till the nuclear configuration of neutrons and protons achieves a stability.

Artificial radio isotopes are produced by neutron irradiation inside a nuclear reactor of stable elements. Examples are Cobalt, Iron, Iodine, Cesium (the later two are products of nuclear fission) etc.

Answer 2

The neutrons and protons that constitute nuclei, as well as other particles that may approach them, are governed by several interactions. The strong nuclear force, not observed at the familiar macroscopic scale, is the most powerful force over subatomic distances. The electrostatic force is also significant. Of lesser importance is the weak nuclear force.

The interplay of these forces is very complex. Some configurations of the particles in a nucleus have the property that, should they shift ever so slightly, the particles could fall into a lower-energy arrangement. One might draw an analogy with a snowfield on a mountain: while friction between the snow crystals can support the snow's weight, a disturbance may facilitate the path to lower potential energy (towards the ground) and an avalanche results.

Such a collapse (a decay event) requires a specific activation energy. In the case of a snow avalanche, this energy classically comes as a disturbance from outside the system, although such disturbances can be arbitrarily small. In the case of an atomic nucleus, the arbitrarily small disturbance comes from quantum vacuum fluctuations. A nucleus (or any excited system in quantum mechanics) can thus spontaneously destabilize. The resulting transformation alters the structure of the nucleus. Such a reaction is thus a nuclear reaction, in contrast to chemical reactions, which involve changes in the arrangement of the outer electrons of atoms.

Some nuclear reactions do involve external sources of energy, in the form of collisions with outside particles. However, these are not considered decay. Rather, they are examples of an induced nuclear reaction. Nuclear fission and fusion are induced nuclear reactions.

Answer 3

A radioactive element is one that decomposes by emitting small subatomic particles. The nucleus of the atom I think finally disintegrates.

Answer 4

a radioactive element is an element that emits gamma radiation. the nucleus of the element decays.

http://en.wikipedia.org/wiki/Radioactive_decay