Neptunium series

The chemistry of neptunium (jjNp) is somewhat similar to that of uranium (gjU) and plutonium (g4Pu), which immediately precede and follow it in the actinide series on the periodic table. The discovery of neptunium provided a solution to a puzzle as to the missing decay products of the thorium decay series, in which all the elements have mass numbers evenly divisible by four the elements in the uranium series have mass numbers divisible by four with a remainder of two. The actinium series elements have mass numbers divisible by four with a remainder of three. It was not until the neptunium series was discovered that a decay series with a mass number divisible by four and a remainder of one was found. The neptunium decay series proceeds as follows, starting with the isotope plutonium-241 Pu-24l—> Am-24l Np-237 Pa-233 U-233 Th-229 Ra-225 Ac-225 Fr-221 At-217 Bi-213 Ti-209 Pb-209 Bi-209. 

The Neptunium Series. During the last war the fourth radioactive series was discovered. This series (Fig. 33-5) is named after its longest-... 

The 4n series - the thorium series The 4n + 1 series — the neptunium series The 4n + 2 series = the uranium-radium series The 4n + 3 series - the uranium-actinium series... 

The series of Radioactive disintegrations the uranium-radium series, the uranium-actinium series, the thorium series, and the neptunium series. The age of the earth. The fundamental particles electron, proton, positron, neutron, positive, negative, and neutral mesons, neutrino. The photon (light quantum) the energy of a photon, hv. Planck s constant. The wave-particle duality of light and of matter. The wavelengths of electrons. 

FlC- 1-2, The three naturally occurring radioactive decay series and the man-made neptunium series. Although (which is the parent to the actinium series) and (which is the parent to the thorium series) have been discovered in nature, die decay series shown here begin with the most abundant Icmg-Uved nuclides. 

A fourth long radioactive decay series, the neptunium series (Fig. 1.2), is conqxrsed of nuclides having mass numbers which divided by 4 have a remainder of 1 (the 4n + 1 series). The name comes from the longest lived A = 4n + I nuclide heavier than Bi, Np, which is considered as the parmt species it has a half-life of 2.14 X 10° y. Inasmuch as this half-life is considerably shorter than the age of the earth, primordial Np no longer exists on earth, and, therefore, the neptunium series is not found as a natural... 

There are lour radiooc.livt, decay series lhat, by sequences of u and emissions, result in the eventual tormalion ot a stable isotope of lead or bismuth Members of each series have mass numbers which are exactly divisible by 4 (the thorium series, 4n), or alter being divided by lour leave remainders of I (the neptunium series, 4n i-1),... 

The only nonnaturaUy occurring radioactive decay series, the neptunium series, has a formula ... 

The neptunium series, because of the relatively short life of its parent, is no longer present in nature. The... 

Through the efforts of many investigators the chemistry of the radioactive elements of the uranium series and the thorium series was unraveled during the first two decades of the twentieth century, and that of the neptunium series during a few years from 1939 on. 

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