According to DigoPaul, the adjective alkaline is used to describe that which has alkali. An alkali, on the other hand, is a metal-type hydroxide that acts as a strong base and has great solubility when in water.
Moving a little further with the definition, we must bear in mind that a hydroxide is a compound that is constituted by the union of the OH- anion with a radical or a chemical element.
The alkalis, therefore, are composed of the hydroxides known as alkalis. There are six elements: francium, cesium, rubidium, potassium, sodium and lithium. These alkalis can be identified in the periodic table within group 1A.
Each alkaline has a single electron in its external energy layer. Due to low ionization energy and reduced electron affinity, alkalis tend to lose this electron, forming a monopositive ion.
In nature, alkalines cannot be found as free elements, but always appear in combination.
Among the properties of alkalis, we can highlight the following:
* effectively conduct electricity and heat;
* when in contact with oxygen and water, they react immediately;
* form hydroxides when they react with water;
* the silver color and the shine of a metal can be seen when they are cast or cut;
* these are low-density metals;
* its color is silver-white;
* their melting points are low and decrease as we descend into the group;
* are soft metals;
* From a chemical point of view, they are the most reactive metals. For this reason, they are not found in nature in a free state, but generally appear as salts.
A observing the periodic table, note that the first element is the hydrogen, which represent with the letter H. It is one of the rarest of the list, because it has only one electron in all its layers. Precisely, it is not easy to assign this element to a group, since on the one hand it gathers all the properties that characterize alkali metals, such as being left with an electron, but also with halogens, due to not having enough numbers electron to present the configuration of a noble gas.
Lithium, on the other hand, is the third element and is an alkali metal itself, with an oxidation number of +1. In its crust, it has three electrons; in its first layer, with two and in the second, with one. It was discovered in the early 19th century and is the lightest solid metal in the world. Its melting point is low, it is soft and, as a good alkali metal, it is very reactive. Today, lithium abounds on our planet and several of its properties make it more similar to the group of alkaline earth metals, among which are magnesium, calcium and beryllium.
Regarding sodium, we can say that its atomic number is 11, the amount of electrons that are distributed in its shell. In proportion to the other alkali metals, it is the fourth most abundant on Earth, and is found especially in sea salt. When exposed to more than 40 °C, it burns.
An alkaline battery is the one that uses potassium hydroxide as an electrolyte, generating a chemical reaction between manganese dioxide and zinc that allows it to obtain energy. The saline batteries instead appeal to zinc chloride or ammonium chloride as the electrolyte, although all provide identical nominal voltage.
