If the radioactivity is induced in an element by irradiation with, for example, neutrons, the process is known as artificial radioactivity. By irradiation we mean exposure to radiation either by accident or by intent.
Artificial disintegration was first achieved by Rutherford when he disrupted nitrogen nucleus with energetic α-particles, to produce first of all an isotope of fluorine. The fluorine nucleus being unstable disintegrates immediately into an oxygen nucleus and a proton thus:
42He + 147N → 189F → 178O + 11H + Energy
In artificial radioactivity an ordinary material, not normally radioactive is made radioactive by bombarding it with radioactive particles
42He + 2713Al
→3015P + 10n → 3014Si + 01e + Energy
Thus phosphorus nuclei which are not stable but radioactive can be produced by bombarding non-radioactive aluminium with α-particles. The radioactive phosphorus nuclei then disintegrates spontaneously into stable Silicon atoms.
The neutron, the proton and the α-particles have been found very effective bombarding projectiles for disintegrating the nuclei of elements. Examples of such bombardments are:
10n + 63Li → 31H + 42He + Energy
10n + 2412Mg → 2411Na + 11P + Energy
42He + 94Be → 126C + 10n + Energy
10n + 5927Co → 6027Co + Energy
Isotopes can be made artificially by bombarding neutrons or protons or deuterons at elements; e.g.
3410S + 10n → 3510S + Energy
7935Br + 10n → 8035Br + Energy
Such artificially produced isotopes are unstable and decay with the emission of α-particles, β-particles and γ-rays. They are therefore called radioisotopes.
Radioisotopes or radioactivity isotopes are isotopes that are made artificially by bombarding neutrons or protons or deuterons at elements.
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