Some Common Elements

Every element has a chemical symbol. In many cases, the chemical symbol is the first two letters of the element s name. While 117 elements have been reported in the chemical literature, you are likely to encounter only 30-40 of these in your nursing studies. The following paragraphs outline a few chemical and physical properties of some common elements as well as some medical applications for the most common elements. This information is not presented for you to memorize. Rather, it is presented for you to gain an appreciation of the myriad of important roles these elements play in your careers in the medical field. 

Aluminum (Al) Aluminum is a silvery white metal with a relatively low density of 2.7 g/cm3. For this reason, aluminum is a popular material for construction. Alloying aluminum with other metals improves its strength. Elemental aluminum does not occur in nature, and must be synthesized by the energy-intensive Hall process. Compounds containing aluminum are found in antiperspirants (aluminum chloride) and antacids (aluminum hydroxide). 

Barium (Ba) Barium sulfate (BaS04) is given orally or as an enema to patients who are undergoing radiographic procedures involving the digestive tract. Because barium is a heavy metal, it is relatively opaque to X-rays and 

Bromine (Br) Elemental bromine exists as a diatomic molecule Br2, and is a reddish-orange, fuming, highly toxic liquid. 

Calcium (Ca) Calcium is a silvery white metal. It does not occur in nature in its elemental form. However, compounds containing calcium are the inorganic components of bone. 

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Relative Integer and Accurate Atomic Masses for Some Common Elements. 

Ideal gas absolute entropies of many compounds may be found in Daubert et al.,"" Daubert and Danner," JANAF Thermochemical Tables,TRC Thermodynamic Tables,and Stull et al. ° Otherwise, the estimation method of Benson et al. " is reasonably accurate, with average errors of 1-2 J/mol K. Elemental standard-state absolute entropies may be found in Cox et al." Values from this source for some common elements are listed in Table 2-389. ASjoqs may also be calculated from Eq. (2-52) if values for AHjoqs and AGJoqs are known. 

An estimate of the polarity of a bond between two atoms may be obtained by reference to the electronegativity scale. The electronegativity values of some common elements are given in Table 5.1. The higher the value the greater the electronegativity. 

Table. S.l Electronegativity values of some common elements...

The most commonly discussed and most useful modes of economic evaluation are cost-benefit and cost-effectiveness analyses. These and other approaches share some common elements, in particular their conceptualization and measurement of costs, but differ in two main respects they measure outcomes differently, and consequently they address slightly different policy or practice questions. 

The simplest form of emission spectroscopy is called flame spectroscopy. Flame spectroscopy can be used to identify some common elements. No fancy equipment is needed. The best way to do flame spectroscopy is to use a platinum loop. This piece of standard laboratory gear consists of a fine, 2-inch (5.1-cm) platinum wire twisted into a loop and embedded in a 4-inch (10.2-cm) glass rod. The only other lab equipment needed is a Bunsen burner or its equivalent. 

The chart shows isotopes of some common elements. Which property is used to name the isotopes ... 

The main detectors used in AES today are photomultiplier tubes (PMTs), photodiode arrays (PDAs), charge-coupled devices (CCDs), and vidicons, image dissectors, and charge-injection detectors (CIDs). An innovative CCD detector for AES has been described [147]. New developments are the array detector AES. With modem multichannel echelle spectral analysers it is possible to analyse any luminous event (flash, spark, laser-induced plasma, discharge) instantly. Considering the complexity of emission spectra, the importance of spectral resolution cannot be overemphasised. Table 8.25 shows some typical spectral emission lines of some common elements. Atomic plasma emission sources can act as chromatographic detectors, e.g. GC-AED (see Chapter 4). 

Table 5.2 Critical constants r(criticai) and P(Criticai) for some common elements and bi-element compounds...

General case. If some measurement errors are correlated, the covariance matrix is not diagonal. It is assumed that we know the sensors which are subjected to correlated measurement errors, for example because they share some common elements (e.g., power supplies). There are then s off-diagonal elements of d>,. .., w),... 

Isotopic abundances are listed either as their sum being 100 % or with the abundance of the most abundant isotope normalized to 100 %. The latter is used throughout this book because this is consistent with the custom of reporting mass spectra normalized to the base peak (Chap. 1). The isotopic classifications and isotopic compositions of some common elements are listed below (Table 3.1). A full table of the elements is included in the Appendix. 

Table 3.1. Isotopic classifications and isotopic compositions of some common elements lUPAC 2001 [4,5]...

Below are some common elements of English words, including root words and prefixes. Take the time to look up any unfamiliar example words in a dictionary. Expanding your vocabulary will help you recognize more words on the test. 

Far Field The far-field boundary conditions also share some common elements. 

Ca for calcium and Cl for chlorine. Some symbols seem to have no relationship to the name of the element, for example Na for sodium and Pb for lead. These symbols come from their Latin names, natrium for sodium and plumbum for lead. A list of some common elements and their symbols is given in Table 2.4. 

Table 2.4 Some common elements and their symbols. The Latin names of some of the elements are given in brackets.

Table 3.2 shows the number of protons, neutrons and electrons in the atoms of some common elements. 

Table A4.1 Atomic weights of isotopes of some common elements 1436...

Table 15.3 Natural Abundances of Isotopes of Some Common Elements...

Whether or not a high-resolution mass spectrometer is available, molecular ion peaks often provide information about the molecular formula. Most elements do not consist of a single isotope, but contain heavier isotopes in varying amounts. These heavier isotopes give rise to small peaks at higher mass numbers than the major M+ molecular ion peak. A peak that is one mass unit heavier than the M+ peak is called the M+l peak two units heavier, the M+2 peak and so on. Table 12-4 gives the isotopic compositions of some common elements, showing how they contribute to M+l and M+2 peaks. 

The adjustment parameters h and k take into account the trends in electronegativity, but are not quantitatively related to the numbers in Fig. 1.43andTable 1.1.The values of h for some common elements and of k for the corresponding C=X n bonds in Table 1.2 have been recommended for use in Equations 1.15 and 1.16. 

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