Boron nucleus, properties

The Group III elements all have three electrons in their outer shell. Most of them form +3 ions by losing all three electrons. Because the boron atom is so small, its nucleus holds very tightly to all its five electrons. Boron usually combines with other elements which have electrons to share, just as carbon combines. It is called a semi-metal because it has some, but not all, of the metallic properties. 

One property of special importance is boron s ability to absorb neutrons. Neutrons are subatomic particles with no charge that occur in the nucleus of nearly all atoms. Boron atoms are able to absorb a large number of neutrons. This makes boron useful in the control rods of nuclear reactors. 

Two naturally occurring isotopes of boron exist boron-10 and boron-11. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element s name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. Boron-10 is the isotope with high neutron-absorbing tendencies described earlier under Physical Properties. ... 

However, even the approximate specification of A is enough to guarantee that the distribution of the electron in space is not spherically symmetrical. The symmetry properties of the boron atom are determined by those of it single 2p electron, so when we say that the free boron atom is spherically symmetric we really mean that the probability distribution of the electron about the nucleus is spherically symmetrical because the direction of A is unknown. 

The presence of non-metal lie elements in metals may affect their properties in a variety of ways. Non-metals may influence mechanical and physical properties such as corrosion resistance, hardness, hot and cold ductility, mechanical strength, conductivity, castability, nucleus forming properties and sinterability. Boron influences the nuclear properties of metals. These effects may be felt at very low concentrations even below 0.1 i g/g. 

Miller, P. S, Fang, K. N., Konda, N. S., and Ts o, P. O. P (1971) Syntheses and properties of adenine and thymine nucleoside alkyl phosphotriesters, the neutral analogs of dinucleoside monophosphates. J. Am. Chem. Soc. 93,6657-6665. Laster, B H., Schinazi, R. F., Fairchild, R. G, Popenoe, E. A, and Sylvester, B (1985) Neutron Capture Therapy, Proc. 2nd Int Sym. (pub. 1986), 46-54. Kobayashi, T and Konda, K. (1984) Boron-10 dosage in cell nucleus for neutron capture therapy—Boron selective dose ratio Proceeding of the First International Symposium on Neutron Capture Therapy, October 12-14,1983, BNL Report No. 51730, pp. 120-127. 

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