Sodium elements

Sodium, element number 11, is a soft and silvery gray metal with a density of 0.97 g/cm3. Since this value is less than the density of water, sodium metal floats (although it reacts violently with the water upon contact). Sodium is so soft that it can be cut and shaped with a butter knife. It is the most abundant of the alkali metals, readily obtained from seawater, and used in a large number of applications. Of all the alkali metals, sodium metal is the one produced and used in industry in greatest quantity. 

The mole and weight fractions of sodium acrylate in the hydrolyzed polymers were determined from sodium elemental analysis and calculated according to equations 1 and 2, respectively. 

A. Production of Sodium. Elemental sodium is produced along with chlorine by the electrolysis of fused NaCl-CaCh mixtures [44-46]. The most popular of the many cell designs, and one still in commercial use, has been the Downs cell. Separate paths of development have led to several different versions, all referred to under the Downs name. Figure 15.12 [47] shows one of these. It operates at 580-600 C on a mixture of 42% NaCl and 58% CaCh. The CaCh lowers the melting point of the batch, reduces the solubility of Na in the bath, and leads to the formation of metallic calcium according to the equilibrium reaction... 

Sodium, element 11, has two electrons in the first energy level and eight electrons in the second energy level, with the remaining electron occupying the 3s orbital in the third energy level ... 

Sodium, element number 11, has ten electrons in inner shells, ls 2s 2p, and one electron in an outer shell, 3r. The ten inner-shell electrons of the sodium atom screen (shield) the outer-shell electron from most of the 11 -t- nuclear charge. Recall from Chapter 4 that the third shell n = 3) is farther from the nucleus than the second shell (n = 2). Thus, we see why sodium atoms are larger than lithium atoms. Similar reasoning explains why potassium atoms are larger than sodium atoms and why the sizes of the elements in each column of the periodic table are related in a similar way. 

The composition of fly ash varies widely, depending upon the fuel. The predominant constituents are oxides of aluminum, calcium, iron, and silicon. Other elements that occur in fly ash are magnesium, sulfur, titanium, phosphorus, potassium, and sodium. Elemental carbon (soot, carbon black) is a significant fly ash constituent. 

The BCC structure is illustrated in figure Al.3,3. Elements such as sodium, tungsten and iron fonn in the BCC structure. The conventional unit cell of the BCC structure is cubic, like FCC, with the length of the edge given by the lattice parameter, a. There are two atoms in the conventional cell. In the primitive unit cell, there is only one atom and the lattice vectors are given by... 

For the next elements, sodium to argon, the = 3 quantum level fills up in the same way as then = 2quantum level. This is shown in Table 1.3. 

The table contains vertical groups of elements each member of a group having the same number of electrons in the outermost quantum level. For example, the element immediately before each noble gas, with seven electrons in the outermost quantum level, is always a halogen. The element immediately following a noble gas, with one electron in a new quantum level, is an alkali metal (lithium, sodium, potassium, rubidium, caesium, francium). 

Let us consider the formation of sodium chloride from its elements. An energy (enthalpy) diagram (called a Born-Haber cycle) for the reaction of sodium and chlorine is given in Figure 3.7. (As in the energy diagram for the formation of hydrogen chloride, an upward arrow represents an endothermic process and a downward arrow an exothermic process.)... 

REACTIONS OF THE ELEMENTS WITH ALKALIS (SODIUM HYDROXIDE)... 

Amorphous boron and the amphoteric elements, aluminium and gallium, are attacked by aqueous solutions of sodium hydroxide and... 

Antimony forms both a + 3 and a + 5 oxide. The + 3 oxide can be prepared by the direct combination of the elements or by the action of moderately concentrated nitric acid on antimony. It is an amphoteric oxide dissolving in alkalis to give antimonates(III) (for example sodium antimonite , NaSb02), and in some acids to form salts, for example with concentrated hydrochloric acid the trichloride, SbCl3, is formed. 

For Middleton s sodium carbonate-zinc method for the detection of elements, see p. 326. 

Most nitrocompounds react vigorously with metallic sodium during the tests for elements present (p. 321). 

In order to detect these elements in organic compounds, it is necessary to convert them into ionlsable inorganie substanees so that the ionic tests of inoiganio qualitative analysis may be applied. This conversion may be accomplished by several methods, but the best procedure is to fuse the organic compound with metallio sodium (Lassalgne s test). In this way sodium cyanide, sodium sulphide and sodium halides are formed, which are readily identified. Thus ... 

Sulphur, as sulphide ion, is detected by precipitation as black lead sulphide with lead acetate solution and acetic acid or with sodium plumbite solution (an alkaLine solution of lead acetate). Halogens are detected as the characteristic silver halides by the addition of silver nitrate solution and dilute nitric acid the interfering influence of sulphide and cyanide ions in the latter tests are discussed under the individual elements. 

Sodium is present in fair abundance in the sun and stars. The D lines of sodium are among the most prominent in the solar spectrum. Sodium is the fourth most abundant element on earth, comprising about 2.6% of the earth s crust it is the most abundant of the alkali group of metals. 

Sodium, like every reactive element, is never found free in nature. Sodium is a soft, bright, silvery metal which floats on water, decomposing it with the evolution of hydrogen and the formation of the hydroxide. It may or may not ignite spontaneously on water, depending on the amount of oxide and metal exposed to the water. It normally does not ignite in air at temperatures below llSoC. 

Commercial production from petroleum ash holds promise as an important source of the element. High-purity ductile vanadium can be obtained by reduction of vanadium trichloride with magnesium or with magnesium-sodium mixtures. 

Rubidium can be liquid at room temperature. It is a soft, silvery-white metallic element of the alkali group and is the second most electropositive and alkaline element. It ignites spontaneously in air and reacts violently in water, setting fire to the liberated hydrogen. As with other alkali metals, it forms amalgams with mercury and it alloys with gold, cesium, sodium, and potassium. It colors a flame yellowish violet. Rubidium metal can be prepared by reducing rubidium chloride with calcium, and by a number of other methods. It must be kept under a dry mineral oil or in a vacuum or inert atmosphere. 

---