The s-blocks contains the elements that make up Alkaline Earth Metals. These metals exhibit a number of observable properties. Alkaline earth metals have similar electronic structures to noble gases. They include 2 electrons in the farthest distant orbital in their atomic structure. This gives them similar properties to noble gases, but they are more reactive and can give up electrons to other substances and form 2+ cations. In addition to being extremely reactive reduction reagents, the alkaline earth metals have a basic structure. These metals can undergo chemical reactions with other metals and are often used in chemical reactions. They are used in many common industrial processes, including metallurgy, construction, and pharmaceuticals. These metals are also important to plant and animal life. They are important because they play multiple roles in biological and chemical processes. They are used in diagnostic tests to detect cancer, disease, and other illnesses. In addition, alkaline earth metals are used in mammography to detect breast cancer and tumours. These elements are also used in radiotherapy for treating bone cancer. They are used in industry, medicine, and glass. Calcium is used in the production of cement and mortar. Strontium is used to make vacuum tubes. Beryllium is the lightest and smallest of alkaline earth metals (Campo. Et al., 2008).
1. What are alkaline earth metals?
Building elements that are included in grouping 2 of the periodical chart are known to as alkaline-earth’s metals. These elements share similar properties, such as their silvery-white appearance and somewhat reactive nature at a standard temperature. They are typically found in their oxidized forms in the earth’s crust. In their oxidized state, these elements can form metal oxides and halide complexes (Kobayashi & Yamashita, 2011).
1.1. Orbital pattern
The valence electron configuration of alkaline earth metals is s 2. This means that the two
electrons involved in chemical bonding move through an orbital range of probabilities that roughly corresponds to a sphere. Similarly alkaline earth metals have high nuclear charges, which attract electrons to the nucleus.
1.2. Structure
The structure of alkaline earth metals is largely governed by the electron correlations between their valence electrons and the valence atoms. Alkaline earth metals are usually positively charged and have a double-shell valence electron configuration.
Figure 1: Alkaline earth metals
2. Elements belonging to the group of alkaline earth metals
These elements include radium, calcium, barium, strontium, and the magnesium’s and berylliums. These metals have a silvery sheen and are so pliable that they can be sliced with a kitchen knife. Description of some important alkaline earth metals is given below (Fromm, 2020).
2.1. Beryllium
Beryllium is a chemical element that is found in nature. It is an element that has several uses. Beryllium, for examples, is commonly employed as a neutrons moderator in nuclear reactors. In fusing ovens, it is employed as a plasma confronting materials. Beryllium is also an element with a very long name: beryllium, whose symbol is Be, has an atomic number of 4. There are 12 different isotopes of beryllium. The stable isotope is beryllium-9, which contains 5 neutrons in its nucleus. Beryllium is also widely used in the aerospace industry, where it is used as a structural component and for high-resolution imaging. It has excellent thermal conductivity and is resistant to attack by nitric acid. It is nonmagnetic, and is used extensively in electronic components.
2.2. Calcium
Calcium has a wide range of applications. Bearings and alloys like steel benefit from this mineral’s presence. In the metal-working industry, it serves as a reduction agent and a bismuth extractor.
2.2.1. Chemical syntheses
Calcium is a metal with a high chemical activity, allowing it to form a variety of compounds. Its large proportion in the earth’s crust (about 1.5%) makes it an important component in technical chemical syntheses. It is found naturally in many minerals, including seawater. Its high concentration in seawater means that it dissolves in water and forms alkalis.
2.2.2. Qualitative reaction
Calcium is highly reactive and must be stored in dark glass with a tight-fitting lid, beneath a layer of kerosene or paraffin. The ion produces a qualitative reaction when exposed to flame. However, demonstrating this reaction with a single piece of calcium is not practical. It is easier to use metallic calcium, such as filings, in the laboratory.
2.3. Barium
Barium is an element found in the periodic table. Its chemical formula is CaF3. Its oxidation state is +2, and it is an ion in the metal ion. It is toxic to mammals, and it can interfere with the potassium ion channel. Several different forms of barium are used in medical imaging. Barium sulfate, a liquid form of the element, is a popular contrast medium in x-rays. Barium is a soft metallic element. It is found primarily in compounds with carbonate and sulfate. It is also used as an alloy constituent. One type of barium alloy is nickel. This alloy readily emits electrons when heated. This type of alloy is often used in spark plug electrodes and electron tubes.
2.4. Strontium and Radium
Strontium and radium are elements that are often associated with cancer. They are similar in composition to calcium and barium, but have different uses. Strontium is commonly used in pyrotechnics, warning flares, and greases, while radium is only used in extremely small amounts in medicine. Strontium is also useful as a by-product of nuclear reactors. Strontium is found in Groups 2 of the scientific chart, including the alkaline earth’s metals. It behaves in a similar way to calcium in that it is used to build bones in humans and animals. Milk, which contains calcium, is commonly recommended for young children, because it is a rich source of calcium that is used to build healthy bones and teeth.
3. Main features
Alkaline earth metals are a class of metals with increasing reactivity. As the name suggests, they react with acids to liberate hydrogen. They are weaker than alkali metals. The reactivity of alkaline earth metals increases with increasing grouping. The amount of energy needed to ionize an element is known as the ionization energy, and the lower the number of electrons, the more reactive it is (Campo, et al., 2008).
3.1. Electronegativity and affinities
Alkaline earth metals have a very similar chemical properties to alkali metals, although the alkaline-earth metals have slightly higher melting points than alkali metals. Alkaline earth metals have an electronegativity and affinities of ns2. Their chemical properties depend on the ease at which they lose their electrons to form divalent cations.
3.2. Ionization enthalpy and electro positivity
Alkaline earth metals are elements that are found in Group 2A of the Periodic Table. They share many traits with their alkali counterparts, but they are less reactive. This means that these metals are able to form strong bonds easily. The metals of this group are also highly electropositive. These elements have a relatively low ionization enthalpy, which means that they are less reactive with water than their alkali counterparts.
3.3. Charge density and reducing ability
The ionic properties of alkaline earth metals are related to their chemical properties. Their smaller atomic sizes result in smaller ionic radii. This decreases their solubility in water. This is due to their charge density, and a smaller ion can be solvated by more water molecules. The ionization energy is inversely related to their reducing ability, meaning that the smaller an ion is, the greater it’s reducing ability.
4. Properties of alkaline earth metals
The properties of alkaline earth metals are very diverse and include their ability to form hydroxides. . These metals share many chemical and physical properties. Their compositions are similar to that of other metals. However, beryllium (Be) is an unusual case in that element does not dissolve in water. Its small atomic size and high ionization energy make it a more reactive metal than the other alkaline earth metals (Kobayashi & Yamashita, 2011; Fromm, 2020).
4.1. Physics of alkaline earth metals
The atomic structure of the alkaline earth metals has been characterized by X-ray diffraction. The atomic radius of these elements increases with increasing atomic number, and their volume decreases with an increase in electron density. The density of alkaline earth metals decreases as they progress from the lightest element (calcium) to the densest metal (radium). In spite of the fact that alkali metals and transitioning metals are distinct from one another, alkaline earth elements are gentler and have a lower density as transitional metals. These metals are smaller than their alkali counterparts and have two valence electrons in their highest energy orbitals. They also have higher melting points than alkali metals. For example, beryllium melts at 1287 ºC. Calcium, magnesium, and radium have melting points of around 750ºC.
4.1.1. Electron correlations
The structure of alkaline earth metals is largely governed by the electron correlations between their valence electrons and the valence atoms. Alkaline earth metals are usually positively charged and have a double-shell valence electron configuration. These typically undergo chemical reactions when exposed to oxygen and water, producing oxidation and hydroxides as byproducts. Mg is an excellent illustration of a metals that is subject to transmutation processes.
4.1.2. Ionization energies
Alkaline earth metals have high ionization energies. This is because the atoms of these metals are smaller and the electrons in their outermost shells are more tightly held. Since the nuclear charges seems related to the ionization energy, a bigger number signifies a higher figure than a smaller one.
4.1.3. Radioactivity
The term “alkaline earth metals” refers to a category of elements in chemistry that all possess a number of common properties. They readily lose two of their outermost electrons to form a cation. The first five members of the group have been studied for their chemistry, but radium is still under research due to its radioactivity.
4.1.4. Ion solubility
The solubility of alkaline earth metal compounds is highly dependent on the cation. In general, alkaline earth metals are water-soluble when combined with nitrates or chlorides. However, when combined with other anions, they are less water-soluble.
4.1.5. Electrochemical properties
Alkaline earth metals are a class of materials with outstanding electrochemical properties. They also possess good electronic conductivity. Moreover, alkaline earth metals can be used as anodes in sodium-ion batteries. However, the limitations in electrochemical properties of the electrode materials limit the potential of these batteries for practical use. Alkaline earth metal vanadates are promising anodes for such batteries.
4.2. Chemistry of alkaline earth metals
Alkaline earth’s metals have different properties and reactivity. These metals are very reactive. They can react with both water and hydrogen. Calcium reacts with hydrogen to form metallic hydrides. Magnesium reacts with water to form hydroxides. This reaction creates a protective oxide coat on the metal. Other alkaline earth metals, such as Be and Mg, react with hydrogen to form saline hydride.
Ca + H2 → CaH2
Be + H2→Be H2
Mg + 2H2O → Mg(OH)2 + H2
4.2.1. Compound
There are several compounds discovered naturally that include alkaline earth metals. For instance, calcium is the body’s most prevalent element and also happens to be its hardest. It is also responsible for making bones hard and strong, and makes them show up white on x-ray images. As a result, calcium is important for maintaining a healthy diet.
4.2.2. Oxides
A chain involving scientific processes may be used to transform alkaline earth’s metals into their oxides. In water, they react with halogens to form oxoacids. Their carbonates are soluble in water and form sulphates or carbonates. Neither mineral is completely insoluble in water, but they can be rendered anhydrous by adding nitric acid or ammonia.
Conclusion
Alkaline-earth’s metals physical structure and their chemical attributes are indicative of metals on the periodic table. However, they are different from other metals in two important ways. The alkaline earth metals are highly reactive. They possess a valence electron in the s1 orbital and are easily ionized. These elements tend to form 2+ cations. The ability of alkaline-earth’s metals to readily mix with different elements to create combinations is another distinguishing feature of these materials. The oxidation phase of alkaline-earth’s metals is +2, and they are exceptional in their potential to transmit electricity. They also have a high dielectric constant and can absorb electrical charge. Their atomic structure is also important in determining their applications. There are several different types of alkaline earth metals, including lithium, magnesium, barium, and strontium. All alkaline earth metals are quite reactive. However, unlike alkali metals, they are rarely found free in nature. They are found in many different compounds. As pure metals, these elements are silvery white. However, surface oxide layers make them look dull.
References
1. Arzamendi, G., Arguinarena, E., Campo, I., Zabala, S., & Gandia, L. M. (2008). Alkaline and alkaline-earth metals compounds as catalysts for the methanolysis of sunflower oil. Catalysis Today, 133, 305-313.
2. Kobayashi, S., & Yamashita, Y. (2011). Alkaline earth metal catalysts for asymmetric reactions. Accounts of chemical research, 44(1), 58-71.
3. Fromm, K. M. (2020). Chemistry of alkaline earth metals: It is not all ionic and definitely not boring!. Coordination Chemistry Reviews, 408, 213193.