Properties of Beryllium and Lithium

Introduction

Beryllium and Lithium are different from by the means of physical and chemical properties. The main difference between them is, Beryllium is diamagnetic and exists in white grey colour, whereas Lithium is paramagnetic and exists in silvery grey metal. They form two different kinds of cations of divalent and monovalent.

What is Beryllium?

Beryllium is an alkaline earth metal with atomic number of 4. It can be represented with the chemical symbol of Be. In this universe, it is considered one of the rarest chemical elements. It has a white-grey colour.

Figure 1 − Atomic structure of Lithium and Beryllium

The valance electrons of Beryllium belong to s orbital; hence, it is known as s-block element. The electronic configuration of Beryllium is [He]2s2. This metal is hard and brittle in nature and has a close-packed hexagonal crystal system. The metal shows a unique stiffness with higher melting point compared to other elements of group 2.

Physical and Chemical properties of Beryllium

The physical and chemical properties of Beryllium are as mentioned below −

Physical properties

The boiling point of the Beryllium is comparatively very high than the other elements in group 2. It has a still greyish appearance. In comparison to the other elements of group 2, it is harder with smallest ionic radii. It shows highest Ionization enthalpy compared with to the other alkaline earth metals.

Chemical Properties

Figure 2 − Properties of beryllium

Beryllium is the only element among alkaline earth metals that is inert to water due to formation of a BeO layer on the surface of metal. It does not even react with the air because of the same reason. Beryllium forms covalent hydrides and halides. It does not react with the hydrogen gas.

• Reasons for Anomalous properties − Two main reasons are behind the Anomalous properties of Beryllium. The first one is the atomic size of Beryllium, which is very small; hence, it does not follow other characteristics of alkaline earth metals group. The second one is the coordination number of Beryllium that is 4, whereas the other group members have the coordination number of 6.

• Difference between Beryllium and other Alkaline Earth Metals − In comparison with other alkaline earth metals, Be does not react with acids and water soluble. Beryllium carbonate stays in an unstable form and the Beryllium Nitrate is anhydrous in nature.

What is Lithium?

Lithium is an alkali metal that has the atomic number of 3. It can be presented with the chemical symbol of Li. Along with Hydrogen and Helium, Lithium is considered one of the earliest elements was present in the time of creation of earth. It shows a crimson coloured flame when it burns, however, in general, it has a silvery white colour.

Physical and Chemical properties of Lithium

The physical and chemical properties of Lithium are as follows −

• Physical properties − It is harder in nature compared to other element in Group 1.. The melting and boiling point of Lithium is 180.50°C and 133 °C respectively. It is considered the lightest metal and it also has the smallest ionic radii. In comparison with other metals of Group 1, it has highest ionization enthalpy.

• Chemical Properties −

Figure 3 − Properties of Lithium

Only Li can exist in stable oxide molecule compared to other elements of Group 1, depending upon atomic or ionic size of the metal. It is less vigorous to react with water than other elements in Group 1. At high temperatures, Lithium reacts with the hydrogen, however, the temperature is kept around 1073 K. Lithium acts as a strongest reducing agent and it forms covalent halides.

• Reasons for Anomalous properties − Two main reasons are behind the Anomalous properties of Lithium. Smallest atomic size of Lithium and very high polarizing power makes it different from other alkali metals.

• Difference between Lithium and other Alkali Metals − Lithium can form the hydrates while the other members are unable to produce. It can form solid compound of hydrogen carbonate unlike other alkali elements in Group 1. Lithium Nitrate decomposes to Lithium oxide under the proper amount of heat.

Lithium and Beryllium both are very important and useful elements. Lithium is used in the production of different types of alloys and one of them is white metal. Beryllium is mixed with Copper to produce very powerful springs. Both metals exist in the same second period in the periodic table.

FAQs

1. What are the common properties of Lithium and beryllium?

Lithium and Beryllium belongs to two separate groups but both have some common properties. These elements can dissolve into water and in both cases exhibits a large number of atomic radii. Because of their small size, these elements have better ionizing energy. Compared to the other alkali metals, the both elements can form better and more stable hydride.

2. What is the reason behind the resemblance between the Beryllium and Aluminium?

The oxides of Beryllium and Aluminium show a major acidic nature and amphoteric in nature. Both of these elements can easily dissolve in strong alkalies to form soluble complexes. These complexes are formed due to polarizing power of the elements

3. What is the diagonal relationship between the Beryllium and Aluminium?

The diagonal relationship refers to the unusual behaviour of the Beryllium and Aluminium. These elements show similar behaviour that matches with each other more than their group member does. For example, these elements have almost equal atomic size, i.e., 31pm. These elements also have the same kind of polarising power.