Group 2A metals

The alkaline earth metals undergo the same kinds of redox reactions that the alkali metals do, but they lose two electrons rather than one to yield dipositive ions, M2+. Because their first ionization energy is larger than that of alkali metals (Figure 6.3), the group 2A metals tend to be somewhat less reactive than alkali metals. The general reactivity trend is Ba > Sr > Ca > Mg > Be. 

Because lithium is a group 1A metal and barium is a group 2A metal, their hydrides have the formulas LiH and BaH2, respectively. Both are ionic hydrides and therefore react with water to give H2 gas and OH ions. Balance the equations either by inspection or by using the method of oxidation numbers (Section 4.9). 

BMC is processed by premix techniques, using the standard sigma-blade mixer. The only change is the use of Group 2a metal oxides and hydroxides. 

Not many ionic hydroxides are soluble except for the hydroxides of the Group 1A and Group 2A metals (except for magnesium—Mg(OH)2 is insoluble). So, the commonly encountered strong bases include the following ... 

The oxides of Group 2A metals (symbolized by M here) react with carbon dioxide according to the following reaction ... 

Beryllium is amphoteric, in contrast to its fellow Group 2A metals. Beryllium metal reacts with aqueous NaOH to produce hydrogen gas and Be(OH)42 . Write a balanced equation for this reaction. What is the oxidizing agent What is the reducing agent ... 

Consider the formation of the ionic compound calcium fluoride from calcium (Ca) and fluorine (F). Calcium, a group 2A metal with the electron configuration [Ar]4s, has two valence electrons. Fluorine, a group 7A nonmetal with the electron configuration [He]2s 2p, must gain one electron to attain the noble gas configuration of neon. 

Group lA and group 2A metals have only one oxidation number. Transition metals and metals on the right side of the periodic table often have more than one oxidation number. To distinguish between multiple oxidation numbers of the same element, the name of the chemical formula must indicate the oxidation number of the cation. The oxidation number is written as a Roman numeral in parentheses after the name of the cation. For example, the compound formed from Fe + and has the formula FeO and is named iron(II) oxide. The compound formed from Fe + and has the formula Fe203 and is named iron(III) oxide. 

List the sulfates of the Group 2A metals in order of increasing solubility in water. Explain the trend. (Hint You need to consult a chemistry handbook.)... 

Helium contains the same number of electrons in its outer shell as do the alkaline earth metals. Explain why helium is inert whereas the Group 2A metals are not. 

The effect of size is also evident in other groups. For example, the oxides of the metals in Group 2A are all quite basic except for the first member of the series beryllium oxide (BeO) is amphoteric. The basicity of an oxide depends on its ionic character. Ionic oxides contain the 0 ion, which reacts with water to form two OH ions. All the oxides of the Group 2A metals are highly ionic except for beryllium oxide, which has considerable covalent character. The small Be " ion can effectively polarize the electron cloud of the... 

Group 1A metal hydroxides [LiOH, NaOH, KOH, RbOH,CsOH] Heavy group 2A metal hydroxides [Ca(OH)2, Sr(OH)2, Ba(OH)2]... 

An 8.65-g sample of an unknown group 2A metal hydroxide is dissolved in 85.0 mL of water. An acid base indicator is added and the resulting solution is titrated with 2.50 M HCl aq) solution. The indicator changes color signaling that the equivalence point has been reached after 56.9 mL of the hydrochbric acid solution has been added, (a) What is the molar mass of the metal hydroxide (b) What is the identity of the metal cation Ca, Sr, Ba ... 

TRENDS FOR GROUP 1A AND GROUP 2A METALS We examine some periodic trends in the chemistry of group 1A and group 2A metals. 

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