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Helium alpha particles

The pure metal of berkelium does not exist in nature and has never been directly artificially produced, although the first isotope of berkelium produced was berkelium-243. It was artificially formed by bombarding americium-241 with the nuclei of helium (alpha particles), as follows " Am+lalpha particle = 2 protons + 2 neutron)—> Bk. (Note Two protons as well as two neutrons are found in the nucleus of helium, and thus the two protons changed the atomic number of americium [ jAm] to berkelium [j Bk].) Today a different process is used to produce berkelium in small amounts, as follows Cm+(5n = neutrons X = gamma rays) —> (becomes) —> Bk + P- = (beta-minus decay). [Pg.325]

Frederick Soddy and William Ramsay discovered that radioactive decay can produce helium (alpha particles). [Pg.232]

Gr. helios, the sun). Janssen obtained the first evidence of helium during the solar eclipse of 1868 when he detected a new line in the solar spectrum. Lockyer and Frankland suggested the name helium for the new element. In 1895 Ramsay discovered helium in the uranium mineral clevite while it was independently discovered in cleveite by the Swedish chemists Cleve and Langlet at about the same time. Rutherford and Royds in 1907 demonstrated that alpha particles are helium nuclei. [Pg.6]

Ernest O. Lawrence, inventor of the cyclotron) This member of the 5f transition elements (actinide series) was discovered in March 1961 by A. Ghiorso, T. Sikkeland, A.E. Larsh, and R.M. Latimer. A 3-Mg californium target, consisting of a mixture of isotopes of mass number 249, 250, 251, and 252, was bombarded with either lOB or IIB. The electrically charged transmutation nuclei recoiled with an atmosphere of helium and were collected on a thin copper conveyor tape which was then moved to place collected atoms in front of a series of solid-state detectors. The isotope of element 103 produced in this way decayed by emitting an 8.6 MeV alpha particle with a half-life of 8 s. [Pg.215]

The most important types of radioactive particles are alpha particles, beta particles, gamma rays, and X-rays. An alpha particle, which is symbolized as a, is equivalent to a helium nucleus, fHe. Thus, emission of an alpha particle results in a new isotope whose atomic number and atomic mass number are, respectively, 2 and 4 less than that for the unstable parent isotope. [Pg.642]

Alpha particle A helium nucleus He2+ ion, 30 emission, 513 scattering experiment, 26... [Pg.681]

The experiment conducted by Rutherford and his co-workers involved bombarding gold foil with alpha particles, which are doubly charged helium atoms. The apparatus used in their experiment is shown in Figure 14-9. The alpha particles are produced by the radioactive decay of radium, and a narrow beam of these particles emerges from a deep hole in a block of lead. The beam of particles is directed at a thin metal foil, approximately 10,000 atoms thick. The alpha particles are delected by the light they produce when they collide with scintilltaion screens, which are zinc sulfide-covered plates much like the front of the picture tube in a television set. The screen... [Pg.244]

There are three common ways by which nuclei can approach the region of stability (1) loss of alpha particles (a-decay) (2) loss of beta particles (/3-decay) (3) capture of an orbital electron. We have already encountered the first type of radioactivity, a-decay, in equation (/0). Emission of a helium nucleus, or alpha particle, is a common form of radioactivity among nuclei with charge greater than 82, since it provides a mechanism by which these nuclei can be converted to new nuclei of lower charge and mass which lie in the belt of stability. The actinides, in particular, are very likely to decay in this way. [Pg.417]

Alpha particles (a particles), which are equivalent to the nucleus of a helium atom (two neutrons and two protons)... [Pg.62]

This equation says that a nitrogen nucleus is composed of seven protons and seven neutrons. An alpha particle, which is identical to a helium ion, has two protons and two neutrons. A highly energetic collision fuses the two nuclei. The result is a rare isotope of oxygen with eight protons and nine neutrons. The leftover proton is ejected. And that proton is what Rutherford detected. [Pg.36]

Alpha particles Helium nuclei composed of two protons and two neutrons that are emitted in radioactive decay. [Pg.117]

Alpha Particle—A positively charged particle ejected spontaneously from the nuclei of some radioactive elements. It is identical to a helium nucleus, i.e., 2 neutrons and two protons, with a mass number of 4 and an electrostatic charge of +2. [Pg.269]

Ans. There is no difference. All three are representations of an alpha particle (or a helium nucleus). [Pg.343]

The alpha particle is a helium nucleus produced from the radioactive decay of heavy metals and some nuclear reactions. Alpha decay often occurs among nuclei that have a favorable neutron/proton ratio, but contain too many nucleons for stability. The alpha particle is a massive particle consisting of an assembly of two protons and two neutrons and a resultant charge of +2. [Pg.28]

The alpha particle is a helium nucleus produced from the radioactive decay of heavy metals and some nuclear reactions. [Pg.34]

Alpha (a.) decay. As we shall see later, the alpha particle, which is a helium nucleus, is a stable particle. For some unstable heavy nuclei, the emission of this particle occurs. Because the a particle contains a magic number of both protons and neutrons (2), there is a tendency for this particular combination of particles to be the one emitted rather than some other combination such as s3Li. In alpha decay, the mass number decreases by 4 units, the number of protons decreases by 2, and the number of neutrons decreases by 2. An example of alpha decay is the following ... [Pg.28]

Helium has long been related to nuclear chemistry because of the formation of alpha particles (a = 4He2+) during the decay of heavy nuclei, an example of which is... [Pg.565]

Primary cosmic rays (cr) emitted by stars bombard the ISM, including planets such as Earth. The particles are 84 per cent protons and 14 per cent helium nuclei stripped of both electrons called alpha particles the remaining 2 per cent are electrons, heavier nuclei and more exotic particles. [Pg.136]

Alpha (a) particles An a particle is composed of two protons and two neutrons, with a charge of +2 essentially, it is a helium nucleus without orbital electrons. Alpha particles usually originate from the nuclear decay of radionuclides of atomic number >82, and are detected in samples containing U, Th, or Ra. Alpha particles react strongly with matter and consequently produce large numbers of ions per unit... [Pg.1753]

He is found in natural gas deposits principally because alpha particles are produced during natural radioactive decay processes. These alpha particles are 4 He nuclei they obtain two electrons from the surrounding material to become helium atoms. This gaseous helium then accumulates with the natural gas trapped beneath the earth. Although other noble gases are produced by radioactive decay—notably 40 Ar—they are not produced in the large quantities that helium is. [Pg.152]

An alpha particle is essentially a helium nucleus with two protons and two neutrons. It is represented as (I Ic or a. As this particle leaves the decaying nucleus it has no electrons and thus has a 2+ charge. However, it quickly acquires two electrons from the surroundings to form the neutral atom. Most commonly, we show the alpha particle as the neutral particle and not the cation. [Pg.293]

Alpha particle Positively charged (+2) radiation particle identical to the nucleus of a helium atom that consists of two protons and two neutrons. [Pg.21]

Radionuclides that do not emit beta particles likely emit alpha particles. An alpha particle is, in effect, a helium atom (two protons and two neutrons) ejected from an unstable nucleus. An alpha particle can only travel a few inches in air and cannot penetrate the outer layers of dead skin cells. Therefore, alpha particles are not external hazards and produce tissue damage only if alpha-emitting radionuclides are ingested, inhaled, or injected. [Pg.63]

If a nucleus is too heavy and its atomic number exceeds 82, it may revert to a more stable arrangement by releasing both neutrons and protons. This is effected by the emission of an alpha particle, which contains two protons and two neutrons and is a helium nucleus, 2He2+. [Pg.197]


See other pages where Helium alpha particles is mentioned: [Pg.24]    [Pg.24]    [Pg.23]    [Pg.769]    [Pg.150]    [Pg.155]    [Pg.320]    [Pg.391]    [Pg.238]    [Pg.415]    [Pg.80]    [Pg.90]    [Pg.7]    [Pg.56]    [Pg.19]    [Pg.305]    [Pg.337]    [Pg.885]    [Pg.573]    [Pg.59]    [Pg.412]    [Pg.6]    [Pg.207]    [Pg.606]    [Pg.226]    [Pg.358]   
See also in sourсe #XX -- [ Pg.76 , Pg.97 , Pg.98 , Pg.112 , Pg.134 ]




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