T’Keyah Driskell & Lyric Williams Alkaline Earth Metals T’Keyah Driskell & Lyric Williams

Introduction In our PowerPoint Presentation, we will be explaining what alkaline earth metals are and some of their uses, reactions, properties, etc. We will tell what the four metals in the group are, and their mass, density, and melting point are. Enjoy!

About alkaline earth metals Alkaline Earth Metals are metallic elements found in the second group of the periodic table. All alkaline earth metals have an oxidation number of +2, making them very reactive. Because of the reactivity, these metals are not found free in nature. The elements of the alkaline earth metals are: Beryllium, magnesium, calcium, strontium, barium, and radium.

Physical and chemical properties The alkaline earth metals are silver colored, soft metals, which react readily with halogens to form ionic salts, and with water, though not as rapidly as the alkali metals, to form strong alkaline (basic) hydroxides. For example, where sodium and potassium react with water at room temperature, magnesium reacts only with steam and calcium with hot water: Beryllium is an exception: It does not react with water or steam, and its halides are covalent. The chemical properties of Group 2 elements are dominated by the strong reducing power of the metals. The elements become increasingly electropositive on descending the Group. All the metals except beryllium form oxides in air at room temperature which dulls the surface of the metal. Barium is so reactive it is stored under oil. All the metals except beryllium reduce water and dilute acids to hydrogen. Magnesium reacts only slowly with water unless the water is boiling, but calcium reacts rapidly even at room temperature, and forms a cloudy white suspension of sparingly soluble calcium hydroxide. Calcium, strontium and barium can reduce hydrogen gas when heated, forming the hydride:

Reactions Hydrogen: All of the Alkaline Earth Metals react with hydrogen to create metallic hydrides. Oxygen: The alkaline earth metals react with oxygen to produce metal oxides. An oxide is just a compound involving oxygen. Halogens: When reacting with halogens, these metals create metal halides. Halide refers to a compound that is one part halogen. Water: Be is shown to not react with water, however Mg, Ca, Sr, and Ba do react to form hydroxides, or bases.

uses Beryllium is used mostly for military applications. but there are other uses of beryllium, as well. Due to its light weight and other properties, beryllium is also used in mechanics when stiffness, light weight, and dimensional stability are required at wide temperature ranges Magnesium has many different uses. One of its most common uses was in industry, where it has many structural advantages over other materials such as aluminum. Magnesium is also often alloyed with aluminum or zinc to form materials with more desirable properties than any pure metal. Magnesium has many other uses in industrial applications, such as having a role in the production of iron and steel, and the production of titanium. Calcium also has many uses. One of its uses is as a reducing agent in the separation of other metals form ore, such as uranium. It is also used in the production of the alloys of many metals, such as aluminum and copper alloys, and is also used to deoxidize alloys as well. Calcium also has a role in the making of cheese, mortars, and cement. Strontium and barium do not have as many applications as the lighter alkaline earth metals, but still have uses. Strontium carbonate is often used in the manufacturing of red fireworks. Barium has some use in vacuum tubes to remove gases. Due to its radioactivity, radium no longer has many applications, but it used to have many. Radium used to be used often in luminous paints. Radium used to be added to drinking water, toothpaste, and many other products. Radium is no longer even used for its radioactive properties

5 grams per cubic centimeter Data Atomic Mass Relative Atomic Mass Melting Point/K Density/ kg Be 4 9.012 1551 1847.7 Mg 12 24.31 922 1738 Ca 20 40.08 1112 1550 Sr 38 87.62 1042 2540 Ba 56 137.33 1002 3594 Ra 88 226 1292 5 grams per cubic centimeter

Conclusion Alkaline Earth Metals are metals in the second group b of the periodic table. In all there are only six of these metals (Be, Mg, Ca, Sr, Ba, and Ra). Each of these metals have there own uses and have some what kind of the same reactions.

What did we learn? What we learned about alkaline earth metals is that they all share similar properties (shiny, silvery white, somewhat reactive metals at standard and temperature and pressure). We learned that all the alkaline earth metals readily loose their two outermost electrons to form charged cations. All alkaline earth metals except beryllium react with water to form strongly alkaline hydroxides. All of these metals except magnesium and strontium have at least one occurring radioisotope. We also learned that Strontium plays an important role in marine aquatic life, and that beryllium and radium are very toxic.

References http://www.rsc.org/chemsoc/visualelements/pages/data/intro_groupii_data.html http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Descriptive_Chemistry/Main_Group_Elements/Group__2%3A_The_Alkaline_Earth_Metals#Alkaline_Earth_Metal_Reactions