Atomic, number weight

There is no need for a premier language to be used in ordering or indexing instead all ordering of atoms are based on atomic number (/weights for isotopes). 

Element Symbol Atomic Atomic number weight Element Symbol Atomic Atomic number weight ... 

Atomic Atomic number weight Density Melting Boiling at 20°C point point (g/cm ) (°C) ( O Linear cogff. of expansion Sp. heat (J/g°C) Thermal conductivity (W/cm C) - Vapour pressure (mm Hg) Total radiation (W/cm ) Total Emissivity Conductivity % lACS Resistivity (tSl cm) - Temp, coeff. of electrical resistivity (°C) Thermal neutron cross section (barns/ atoms) ... 

Table of Elements with Atomic Number, Weights, and First and Second Ionization... 

Though individual atoms always have an integer number of amus, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element. Isotopes can have a weight either more or less than the average. The average number of neutrons for an element can be found by subtracting the number of protons (atomic number) from the atomic mass. 

Atomic number Element CAS Registry Number Symbol Atomic weight Discoverers and date of discovery... 

American Society of Mechanical Engineers American Society for Testing and Materials atomic number atomic weight average... 

Iodine [7553-56-2] I, atomic number 53, atomic weight 126.9044, is a nonmetaUic element belonging to the halogen family in Group 17 (VIIA) of the Periodic Table. The only stable isotope has a mass number of 127. There are 22 other iodine isotopes having masses between 117 and 139 14 of these isotopes yield significant radiation. 

Lead, atomic number 82, is a member of Group 14 (IVA) of the Periodic Table. Ordinary lead is bluish grey and is a mixture of isotopes of mass number 204 (15%), 206 (23.6%), 207 (22.6%), and 208 (52.3%). The average atomic weight of lead from different origins may vary as much as 0.04 units. The stable isotopes are products of decay of three naturally radioactive elements (see Radioactivity, natural) comes from the uranium series (see Uraniumand... 

Manganese [7439-96-5] atomic number 25, atomic weight 54.94, belongs to Group 7 (VII) ia the Periodic Table. Its isotopes are Mn, Mn, Mn,... 

Aluminum [7429-90-5] Al, atomic number 13, atomic weight 26.981, is, at 8.8 wt %, the third most abundant element in the earth s cmst. It is usually found in siUcate minerals such as feldspar [68476-25-5] clays, and mica [12001 -26-2]. Aluminum also occurs in hydroxide, oxide—hydroxide, fluoride, sulfate, or phosphate compounds in a large variety of minerals and ores. 

Tantalum [7440-25-7] atomic number 73, is the heaviest element in Group 5 (VA) of the Periodic Table. This tough, ductile, silvery gray metal has an atomic weight of 180.948 amu. The element was discovered by A. K. Ekeberg in 1802 in minerals taken from Kimito, Finland, and Ytterby, Sweden (1). 

Titanium, Ti, atomic number 22, relative atomic mass 47.90, is the ninth most common element (ca 0.6% by weight) and is widely distributed in the earth s cmst. It is found particularly in the ores mtile, Ti02, and ilmenite, FeTiO. ... 

Here Pyj is the structure factor for the (hkl) diffiaction peak and is related to the atomic arrangements in the material. Specifically, Fjjj is the Fourier transform of the positions of the atoms in one unit cell. Each atom is weighted by its form factor, which is equal to its atomic number Z for small 26, but which decreases as 2d increases. Thus, XRD is more sensitive to high-Z materials, and for low-Z materials, neutron or electron diffraction may be more suitable. The faaor e (called the Debye-Waller factor) accounts for the reduction in intensity due to the disorder in the crystal, and the diffracting volume V depends on p and on the film thickness. For epitaxial thin films and films with preferred orientations, the integrated intensity depends on the orientation of the specimen. 

Silicon has an atomic number of 14 and an atomic weight of 28.06. It is a hard, brittle substance crystallising in a diamond lattice and has a specific gravity of 2.42. The elemental material is prepared commercially by the electrothermal reduction of silica. 

In summary, it is evident that the only moderators of merit are based on elements of low atomic weight. Practically, this limits the choice to elements of atomic number less than sixteen. Gases are of little use as moderators because of their low density, but can be used effectively in chemical compounds such as HjO and DjO. The choice of potential moderators of practical use thus rapidly reduces to the four materials shown in Table 3. Comparing the candidate moderators in Table 3 with our requirements listed above we may note ... 

Iodine (from the Greek, iodines, meaning violet) has an atomic weight of 126.9044, atomic number 53, melting point 113.5° C, and boiling point 184.35° C. As a gas,... 

Atomic weights are known most accurately for elements which have only 1 stable isotope the relative atomic mass of this isotope can be determined to at least 1 ppm and there is no possibility of variability in nature. There are 20 such elements Be, F, Na, Al, P, Sc, Mn, Co, As, Y, Nb, Rh, I, Cs, Pr, Tb, Ho, Tm, Au and Bi. (Note that all of these elements except beryllium have odd atomic numbers — why )... 

Some of the important properties of Group 5 elements are summarized in Table 22.1. Having odd atomic numbers, they have few naturally occurring isotopes Nb only 1 and V and Ta 2 each, though the second ones are present only in very low abundance 0.250%, Ta 0.012%). As a consequence (p. 17) their atomic weights have been determined with considerable precision. On the other hand, because of difficulties in removing all impurities, reported values of their bulk properties have often required revision. 

Name Symbol Atomic Number Atomic Weight Footnotes Name Symbol Atomic Number Atomic Weight Footnotes... 

Atomic number Atomic volume Atomic weight Valency... 

Atomic number Atomic weight Crystal structure Melting Density Thermal Electrical resistivity (at 20°C) Temperature coefficient of resistivity Specific Thermal Standard electrode potential Thermal neutron absorption cross-section. 

NAME SYMBOL ATOMIC NUMBER ATOMIC WEIGHT NAME SYMBOL ATOMIC NUMBER ATOMIC WEIGHT... 

I became increasingly interested in triads of elements, partly because of their historical importance. As I claimed in my book, the discovery of atomic weight triads represents the first major hint that there exists some regularity that underlies the elements.21 Triads represent the first hint of a systematic and quantitative foundation between the numerical properties of the elements. Now since atomic weight was replaced by atomic number, it is... 

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