por What are alkaline earth metals?
The alkaline earth metals They are the elements of group 2 (formerly called group 2A) of the periodic table. That is to say that they are formed by the 6 elements of the second column of the periodic table that go from beryllium (Be) to radium (Ra).
They are a fairly reactive and relatively common group of metallic elements. They have only two valence electrons located in an s orbital. For this reason, they belong to the s block of the periodic table.
The name “alkaline earth” comes from the union of the words “alkaline”, which is another way of saying basic, and earth, which is what oxides were called before. So alkaline earth metals literally means metals that form basic oxides.
These metals have many applications that make them important in our current society, especially magnesium. These applications are due to their particular properties, which are described below.
Properties of alkaline earth metals
They have metallic appearance
All alkaline earth metals have a silvery color with a metallic luster. Radon is also radioactive so it glows in the dark emitting a characteristic green light.
They are low-dense metals.
All alkaline earth metals are denser than water, but they are less dense than most other metallic elements on the periodic table.
Densities in this group range from 1.54 g/cm3 for calcium to 5.5 g/cm3 for radium, which is considerably lower than the densities of other metals such as iron (7.9 g/cm3), copper (9.0 g/cm3), lead (11.3 g/cm3) and mercury (13.5 g/cm3), to name a few.
They have relatively low melting and boiling points.
Being metals, their melting and boiling points are higher than those of most non-metals. However, they are lower than the melting and boiling points of most other metals, with a few exceptions.
have valence +2
Due to their electronic configuration, these metals tend to lose two electrons when they react with other elements such as non-metals. For this reason, its only valence is +2.
They are relatively reactive
The alkaline earth metals are much more reactive than metals such as iron or copper, but they are less reactive than the alkali metals (group 1 elements). The lower it is in the group, the more reactive the metal is.
For example, beryllium (the first of the group) does not react with water while the next two can react with hot water and the last ones can even react with cold water.
They react with air to form basic oxides.
These metals tend to form basic oxides when they react with oxygen in the air. In fact, this is why they are called alkaline earth. These oxides, when dissolved in water, become hydroxides that produce alkaline or basic solutions.
Alkaline Earth Metal Applications
In the tech industry
Some of the alkaline earth metals are used in the manufacture of semiconductors. These are essential in the construction of electronic circuits such as those found in virtually all modern electrical devices, from computers and mobile phones, to washing machines, cars and more.
in the food industry
Calcium is an essential nutrient for life. It is part of the structure of bones and has other important functions in the body. For this reason, this element is added as a fortifier to many foods from cereals to dairy products. In addition, it is also used in the manufacture of cheese.
In the automobile industry
Some of the alkaline earth metals have very good mechanical properties, which means that they are hard and strong. In addition, they are resistant to corrosion, which is why they are frequently used in the manufacture of luxury automobile wheels as well as other parts thereof.
in the military industry
Due to their mechanical properties and low density, metals such as magnesium and beryllium are used in the construction of combat planes, satellites and helicopters.
In addition, due to their electrical properties, they are also used in the manufacture of different types of sensors and optical and electronic systems that the military industry uses to create weapons and communication systems.
The six alkaline earth metals
There are only six alkaline earth metals. Below is a brief description of each of them:
Beryllium (Be)
It is element number 4 on the periodic table and the first in the group of alkaline earth metals. It is a very light, strong metal with unique properties that make it useful in the manufacture of semiconductors.
Magnesium (Mg)
Magnesium is a relatively light, silvery metal with a low melting and boiling point (compared to other metals). It is very hard and resistant and is frequently used in the manufacture of automobile parts and as an additive in the preparation of alloys such as certain types of steel.
It is the second alkaline earth metal and element number 12 on the periodic table. Like other elements in this group, it is an essential nutrient for life.
Calcium (Ca)
Calcium is the 5th most abundant element in the earth’s crust. It is found as calcium carbonate in many minerals and rocks and is also an essential element for life due to its role in bone formation and its importance in the nervous system.
This metal is the element number 20 of the periodic table, it is in the fourth period and it is the third alkaline earth metal.
Strontium (Sr)
The 38th element and fourth alkaline earth metal is strontium. It is heavier than calcium, but closely resembles it in terms of its chemical and physical properties. In fact, strontium can replace calcium in the bones.
This is especially problematic when we are exposed to radioactive strontium that is produced after a nuclear reaction, since, by sticking to the bones, it is very difficult to remove from the body and gradually poisons us with radiation.
Barium (Ba)
This element has atomic number 56 and also has properties quite similar to those of calcium and strontium. It is a fairly soft and highly reactive metal that does not occur in elemental form in nature. It is one of the alkaline earth metals with the greatest metallic character.
Radius (Ra)
The last element in the alkaline earth group is radium, a radioactive metal (hence its name) that emits a dim green light that is easy to see in the dark.
It used to be widely used in the preparation of glow-in-the-dark paints, but after it was discovered how dangerous radioactivity is to health, its use was banned.