The inert gases

John William Strutt, the third Lord Rayleigh, was born at Terling on November 12,1842. His ability for clear thinking and self-expression was evident in his student days, and when he was Senior Wrangler in the Tripos in 1865, one of his examiners remarked, Strutt s papers were so good that they could have been sent straight to press without revision (41). 

John William Strutt, the Third Lord Rayleigh, 1842-1919. 

Professor of physics at Cavendish Laboratory, Cambridge. He made elaborate investigations of the electrochemical equivalent of silver and of the combining volumes and compressibilities of gases. His observation that nitrogen prepared from the atmosphere is heavier than nitrogen prepared from ammonia led to the discovery of argon, the first noble gas. He also contributed to optics and acoustics. 

After the great physicist Clerk Maxwell died in 1879, Lord Rayleigh became his successor at the Cavendish Laboratory, Cambridge. During his professorship the classes increased in size, and women from Girton and Newnham colleges were for the first time admitted on the same terms as the men. Since he was allowed insufficient funds for the purchase of new apparatus, he contributed ,500 of his own money and solicited his friends for similar contributions until he had collected 1500 (3). 

In 1882 Lord Rayleigh told the British Association that he had begun an investigation of the densities of hydrogen and oxygen to find out whether or not the ratio is exactly 1 to 16 in accordance with William 

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The FCC structure is illustrated in figure Al.3.2. Metallic elements such as calcium, nickel, and copper fonu in the FCC structure, as well as some of the inert gases. The conventional unit cell of the FCC structure is cubic with the lengdi of the edge given by the lattice parameter, a. There are four atoms in the conventional cell. In the primitive unit cell, there is only one atom. This atom coincides with the lattice pomts. The lattice vectors for the primitive cell are given by... 

Dalgarno A and Kingston A E 1961 van der Waals forces for hydrogen and the inert gases Proc. Phys. Soc. London 78 607... 

Since 1916 it has been discovered that some noble gases (originally called the inert gases) do form compounds and also there are many reactions known in which elements do not achieve a noble gas configuration. Nevertheless, the theory was a considerable advance towards modem ideas and provides a good basis for discussion. 

Gases used in the manufacture of semiconductor materials fall into three principal areas the inert gases, used to shield the manufacturing processes and prevent impurities from entering the source gases, used to supply the molecules and atoms that stay behind and contribute to the final product, and the reactive gases, used to modify the electronic materials without actually contributing atoms or molecules. 

The inoigaiiic chemistiy of ozone is extensive, encompassing virtually every element except most noble metals, fluorine (qv), and the inert gases. Repotted second-order rate constants (L/(mol-s)) at 20—23°C refer to the disappearance of ozone unless otherwise stated. 

Tantalum. Above 300°C (570°F), the possibihty of reactivity of tantalum with all gases except the inert gases. Below 300°C (570°F), the possibility of embrittlement of tantalum by nascent (monatomic) hydrogen (but not molecular hydrogen). Nascent hydrogen is produced by galvanic action or as a product of corrosion by certain chemicals. 

Either UV-VIS or IR spectroscopy can be combined with the technique of matrix isolation to detect and identify highly unstable intermediates. In this method, the intomediate is trapped in a solid inert matrix, usually one of the inert gases, at very low temperatures. Because each molecule is surrounded by inert gas atoms, there is no possiblity for intermolecular reactions and the rates of intramolecular reactions are slowed by the low temperature. Matrix isolation is a very useful method for characterizing intermediates in photochemical reactions. The method can also be used for gas-phase reactions which can be conducted in such a way that the intermediates can be rapidly condensed into the matrix. 

In the Yukawa potential, A is an inverse range parameter. The value A = 1.8 is appropriate for the inert gases. Each of the above potentials has a hard core. Real molecules are hard but not infinitely so. A slightly softer core is more desirable. The Lennard-Jones potential... 

The analyses of gases in the oil industry comprises the determination of the inert gases (He, Hj, O2, Ar and N2), low-boiling compounds (CO, CO2, H2S, COS) and the lower hydrocarbons, saturated and unsaturated, up to hexane. Some special samples. Such as natural gas, have to be analysed for low concentrations of higher-boiling compounds (up to CiqS) since such compounds have an important influence on the calorific value and dew point. 

The physical properties of the inert gases are shown in Table 6-III. There is much information contained in this table, and we shall examine it in parts. 

Fig. 6-3. The correlation of boiling point and number of electrons per atom for the inert gases.

With this in mind, let us explore the chemistry of all of the elements immediately adjacent to the inert gases. These two vertical columns of the periodic table are called the alkalies and the halogens. 

Table 6-V lists the same properties for the alkali metals that were listed in Table 6-III for the inert gases.

The atomic volumes of the alkali metals increase with atomic number, as do those of the inert gases. Notice, however, that the volume occupied by an alkali atom is somewhat larger than that of the adjacent inert gas (with the exception of the lithium and helium—helium is the cause of this anomaly). The sodium atom in sodium metal occupies 30% more volume than does neon. Cesium occupies close to twice the volume of xenon. 

The alkali metals are exact opposites of the inert gases in chemical reactivity. These metals react... 

The alkali metals are extremely reactive. Thus, there is a dramatic change in chemistry as we pass from the inert gases to the next column in the periodic table. The chemistry of the alkali metals is interesting and often spectacular. Thus, these metals react with chlorine, water, and oxygen, always forming a +1 ion that is stable in contact with most substances. The chemistry of these +1 ions, on the other hand, is drab, reflecting the stabilities of the inert gas electron arrangements that they have acquired. 

Here we find a continuation of the trend displayed by the inert gases and alkali metals. Compare the atomic volumes of the three adjacent elements in the solid state ... 

What is the significance of the trends in the boiling points and melting points of the inert gases in terms of attractions among the atoms ... 

An alkali element produces ions having the same electron population as atoms of the preceding inert gas. In what ways do these ions differ from the inert gases In what ways are they alike ... 

Explain how these energies are consistent with the proposal that the electron arrangements of the inert gases are specially stable. 

How do the trends in physical properties for the halogens compare with those for the inert gases Compare boiling points, melting points, and atomic volumes. 

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