Alkaline Earth Metals are the second group of chemical elements in the Periodic table. Group 2 consists of the following Alkaline Earth Metals: Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). These Alkaline Earth Metals are all found naturally on our planet and they have a variety of periodic traits, which they share, in terms of physical and chemical properties. They are named after their basic Alkaline Earth metal oxides.
Physical Characteristics of the Alkaline Earth Metals
All Alkaline Earth Metals in the Periodic table have similar physical properties, which they share as group 2 periodic trends. They appear in silver-white hues with a shiny, polished surface. These group 2 chemical elements react with water, oxygen and group 17 elements, known as Halogens. Their relatively low density increases as the elements go further down the Periodic table, with Beryllium having a density of 1.85 g/cm3, and Radium having a 5.5 g/cm3 density.
Chemical Properties of the Alkaline Earth Metals
All group 2 elements are somewhat reactive at a standard temperature of 0 C, 32 F, or 273.15 K. The basic Alkaline Earth Metal structure features an outer S electron shell. They form a +2 charge and have an oxidation state of +2. Their similar electronic configuration results in group trends in chemical reactions. Their standard melting and boiling points are also quite low, as are their first and second ionization energies. As the elements move further down the Periodic table, their atomic weight and covalent radii increase, while their electronegativity decreases. Their chemical reactions may vary – from forming oxides as a result to oxidation, to forming ionic halides from their reaction with Halogens. Alkaline Earth Metals have a distinctive white, brick red, crimson red or apple green color when subjected to a flame test.
All Alkaline Earth Metals have a strong reaction to water, apart from Beryllium. When exposed to water, these group 2 elements form alkaline hydroxides. Beryllium is perfectly soluble. The rest of the Alkaline Earth Metal elements’ hydroxides have an increase in solubility as their atomic numbers in the Periodic table increase. Due to their strong chemical reaction to water Alkaline Earth Metals need to be handled with special care. The heavier group 2 elements show a more vigorous water reaction compared to the lighter Alkaline Earth Metals.
Uses and applications of Alkaline Earth Metals
Alkaline Earth Metals can be destructive and their radioactivity levels make them unsafe for most industries. However, they play a relative role in metallurgy, electronics, and science.
For example, Strontium has been used in neuroscience in order to test neurotransmissions. Beryllium and its compounds are used in the military, as well as in other industries for heat conduction and electrical insulation. Magnesium finds application in the food industry and in metallurgy as it is used in the manufacturing of other materials like titanium, steel and iron. Barium sulfate is useful in the petroleum industry. Calcium is used in the manufacturing of some food items and in cement production. Since Radium is highly toxic it doesn’t have any commercial application. It also doesn’t have any application in radioactivity tests, because there are other elements and compounds, which are safer than Radium.
Alkaline Earth Metals on Earth
All group 2 elements in the Periodic table occur naturally on Earth. Apart from Calcium and Beryllium the rest of the Alkaline Earth Metals were discovered in the early 1600s. The last Alkaline Earth Metal element, Radium, was discovered in 1898. All of these elements are naturally occurring in the Earth’s crust. They can be found in the soil, in minerals and rocks, and even in freshwater. Calcium is the 5th most abundant element on our planet, while Beryllium has a concentration of 6ppm in Earth soils.