Alkali metals – Group 1 elements – Properties

What are Alkali Metals ?

Alkali Metals are the very first group of chemical elements in the Periodic table. The Alkali Metals are the following elements: Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (CS), and Francium (Fr), and they all fall under the group 1 elements. Of all other groups in the Periodic table, the Alkali Metals are the best example of a group of periodic traits in physical and chemical properties, as they all bear similarities to each other in terms of physical characteristics and chemical reactivity.


Physical Characteristics of the Alkali Metals

All Alkali Metals in the Periodic table appear shiny, nearly translucent, and are extremely soft. They can be easily cut with a knife, which would result in them losing their shiny polish as a result of oxidation, which occurs when they are exposed to oxygen. The density of all Alkali Metals is severely low and they all have a weak metallic bonding.



Chemical Properties of the Alkali Metals

All metals from group 1 have low melting and boiling points. On the other hand, every single one Alkali Metal in the Periodic table has a large atomic and ionic radius, and a high electrical and thermal conductivity. They have a +1 oxidation state and they are highly radioactive. As their atomic numbers progress further down on the Periodic table, their atomic radius and chemical reactivity increases, while their electronegativity and heat of vaporization decreases. All Alkali Metals have an Ns1 electron configuration and all of them have a very distinctive flame color due to their outer S electron’s easy excitation. The high chemical reactivity of all group 1 elements makes them impossible to store in any other state than in a container with mineral oil.



Water reaction

Every single one of the Alkali Metals is highly radioactive when exposed to water. They have a vigorous, explosive and calamitous reaction to cold water. Group 1 elements produce aqueous solutions of Alkali-based hydroxide and they release hydrogen gas. As the elements move down the Periodic table, their reaction to water becomes more explosive. The explosion is the final result of the melting process of Alkali Metals in water. During the melting process the water ionizes the surface of the Alkali Metal, which results in a positively charged Alkali Metal and negatively charged ions in the water. The increased ionization causes a vigorous explosion.


Alkali Metals - Group 1 elements in periodic table of chemical elements


Uses and applications of Alkali Metals

Group 1 elements of the Periodic table have a large application in electronics, medicine, pyrotechnics, metallurgy, gardening, and technology.

For example, Potassium is of extreme importance for plant nutrition, so it is used as a fertilizer and a stabilizer of pH levels. Sodium can be used in metallurgy for the polishing of other materials, and of course – as table salt. Lithium is used in the manufacturing of ceramics, glass, batteries and lubricating greases. Rubidium and Cesium are the core elements in the manufacturing of atomic clocks, which is what makes atomic clocks so exceptionally accurate. While Francium and its compounds have no commercial function, this element’s compounds are used in many spectroscopy studies and quantum physics experiments because of their simple atomic structures and distinctive atomic energy levels.


Alkali Metals on Earth

All Alkali Metals in the Periodic table have extremely high reactivity, which is why they do not occur in natural, pure forms on our planet. Due to their dangerous reactivity with water and oxygen, these elements can be found close to the Earth’s surface, and they are concentrated mainly in natural minerals with low density. Some group 1 elements, such as Cesium, Rubidium and Potassium, are completely incompatible together. Because of their large ionic radius they cannot concede with one another. Sodium, the most common Alkali Metal, forms around 2.6{f55234ca3553991fddb3c1407133ac611f8d4d4a914364eb7c0c7952d8e2a5f9} of our planet’s crust surface.