Alkali Metals
Alkali metals are a group of highly reactive elements found in Group 1 of the periodic table. They include lithium, sodium, potassium, rubidium, cesium, and francium. These metals are known for their softness, low melting points, and tendency to form strong alkaline solutions when they react with water.
4 Key excerpts on "Alkali Metals"
eBook - ePub- Atef Korchef(Author)
- 2022(Publication Date)
- CRC Press(Publisher)
...They can form alloys with metals. Readily form glasses React with the halogens to form compounds Since metals tend to lose electrons and non-metals tend to gain electrons, metals and non-metals form ionic compounds with each other, such as Fe 2 O 3 and NaCl. Metals can be divided into Alkali Metals, alkaline earth metals, transition metals, lanthanides and actinides. Lanthanides and actinides form the rare earth elements. Non-metals include halogens and noble gases (Figure 7.5). FIGURE 7.5 Metals are divided into Alkali Metals, alkaline earth metals, transition metals, lanthanides and actinides. Non-metals include halogens and noble gases. 7.3.1 Alkali Metals Atoms of the Alkali Metals present a valence shell (ns) and have one valence electron. The alkali family is found in the first column (Group 1) of the periodic table of elements. They include, among others, lithium (Li), sodium (Na) and potassium (K). Note that Alkali Metals do not include hydrogen, even though hydrogen belongs to the first group. Hydrogen is a nonmetal. The valence shell of the alkali family is incomplete (ns 1). They are the most reactive metals. Elements that are reactive bond easily with other elements to make compounds. That is why, in nature, the alkali elements are not found free; they are always bonded with another element. 7.3.2 Alkaline Earth Metals Alkaline earth metals present a valence shell (ns) and have two valence electrons. They are found in Group 2 of the periodic table of elements. The valence shell of the alkaline earth family is completely filled (ns 2). Alkaline earth metals include, among others, beryllium (Be), magnesium (Mg) and calcium (Ca). 7.3.3 Transition Metals Transition metals are elements where the atom has an incomplete d subshell, or which can give rise to cations with an incomplete d subshell. Transition metals are found from Group 3 to Group 12 in the periodic table of elements...
eBook - ePub- Allen J. Bard(Author)
- 2017(Publication Date)
- Routledge(Publisher)
...23 Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium * HIROYASU TACHIKAWA Jackson State University, Jackson, Mississippi I. Characteristics of the Group The elements of this group have one s electron outside a noble gas core and the state of the monoatomic gas atoms is s 1 (2 S 1/2). Because of the similarity and simplicity of the chemistry, the various thermodynamic properties will be discussed for the group as a whole, with the exception of francium. The ionization energy, particularly the first ionization energy, of the elements of this group is very low. The second ionization energies are approximately 10 times higher than the first; thus the chemistry of the Alkali Metals is almost entirely the chemistry of their +1 cations. Because of the strong electropositive nature of the Alkali Metals, the elements behave as the strongest reducing agents and react to form compounds with a very high degree of ionic bonding. The cations have low charge and large size, so that the lattice energies of their salts are relatively low. Consequently, most of the salts are dissociated completely in aqueous solution. In fact, salts with a solubility of less than 0.01 M are very rare. The hydroxides are the strongest bases available. The standard thermodynamic states of the elements are the solid metals. At low concentrations of the metal vapors, the gases are monoatomic because of the weak bonding between atoms. At higher concentrations appreciable formation of the diatomic molecules occurs. The properties of alkali metal compounds vary systematically, particularly the properties of K, Rb, and Cs. Sodium does not deviate from the regular trends nearly as much as Li does. In many of its properties, Li is quite different from the other Alkali Metals. Some compounds of lithium, such as fluoride, carbonate, and phosphate, are relatively insoluble, and those of the other Alkali Metals are reasonably soluble...
eBook - ePubChemistry
Concepts and Problems, A Self-Teaching Guide
- Richard Post, Chad Snyder, Clifford C. Houk(Authors)
- 2020(Publication Date)
- Jossey-Bass(Publisher)
...An element in Group VIIIA may be generalized by its family name as a(n) (noble gas, alkaline earth, alkali metal) _______. Answer : noble gas Group IA on the left side of the chart is often called by the family name of Alkali Metals (with the exception of hydrogen). These elements can react vigorously with water to form strong alkaline solutions. If a friend told you that aluminum (Al) was an alkali metal, would he be right or wrong? _________ Answer : wrong (Aluminum is located in Group IIIA and the Alkali Metals are all located in Group IA.) Group IIA elements are known as the alkaline earth metals because the oxides of these metals (chemical compounds of the metals and oxygen) form alkaline solutions in water. The element potassium (K) can be classified as a(n) (noble gas, alkaline earth, alkali metal) _________. Answer : alkali metal (Group IA) The element Ba (barium) can be classified as a(n) (alkali metal, alkaline earth, or noble gas) _________. Answer : alkaline earth (Group IIA) An unknown element is placed in water. A vigorous reaction takes place, and the result is an alkaline solution. Of which family is the element probably a member: alkaline earth, alkali metal, or noble gas?__________ Answer: alkali metal (Alkali Metals react directly with water to form alkaline solutions. The oxides of alkaline earth elements react with water to form alkaline solutions.) The elements in Group VIIA are known as the halogens, which means “salt formers.” Elements from the halogen family combine with metals to form compounds known as salts. Common table salt (NaCl) is made up of sodium (Na) and chlorine (Cl). These two elements (Na and Cl) are members of what families or groups? Na: _________ Cl: _________ Answer: Group IA, the Alkali Metals (either answer is acceptable); Group VIIA, the halogens (either answer is acceptable). Strontium (Sr) is an element in the _________ family...
eBook - ePubLight Alloys
Metallurgy of the Light Metals
- Ian Polmear, David StJohn, Jian-Feng Nie, Ma Qian(Authors)
- 2017(Publication Date)
- Butterworth-Heinemann(Publisher)
...Ten other elements that are classified as metals are lighter than titanium but, with the exception of boron in the form of strong fibers embedded in a suitable matrix, none is used as a base material for structural purposes. The Alkali Metals lithium, potassium, sodium, rubidium, and cesium, and the alkaline earth metals calcium and strontium are too reactive, whereas yttrium and scandium are comparatively rare. 1.1.1 Characteristics of light metals and alloys The property of lightness translates directly to material property enhancement for many products since by far the greatest weight reduction is achieved by a decrease in density (Fig. 1.1). This is an obvious reason why light metals have been associated with transportation, notably aerospace, which has provided great stimulus to the development of light alloys during the last century. Strength:weight ratios have also been a dominant consideration and the central positions of the light alloys based on aluminium, magnesium, and titanium with respect both to other engineering alloys and to all materials are represented in an Ashby diagram in Fig. 1.2. The advantages of decreased density become even more important in engineering design when parameters such as stiffness and resistance to buckling are involved. For example, the stiffness of a simple rectangular beam is directly proportional to the product of the elastic modulus and the cube of the thickness. The significance of this relationship is illustrated by the nomograph shown in Fig. 1.3 which allows the weights of similar beams of different metals and alloys to be estimated for equal values of stiffness. An iron (or steel) beam weighing 10 kg will have the same stiffness as beams of equal width and length weighing 7 kg in titanium, 4.9 kg in aluminium, 3.8 kg in magnesium, and only 2.2 kg in beryllium. The Mg–Li alloy is included because it is the lightest (relative density 1.35) structural alloy that is available commercially...
