The Chemical Properties of the Group 1 and Group 2 Elements on the Periodic Table

Alkali metals react with a wide range of nonmetals because they are the most electropositive (least electronegative) of all elements. Lithium mimics Group 2 (IIa) of the periodic table in chemical reactivity more than the other metals in its own group. It is less reactive with water, oxygen, and halogens than the other alkali metals, but more reactive with nitrogen, carbon, and hydrogen.

The elements that make up group 2 of the current periodic table are known as alkaline earth metals.This category includes beryllium, magnesium, calcium, strontium, barium, and radium. The physical and chemical properties of the elements in this group are relatively similarAll alkaline earth metals, for example, are silvery-white solids under normal circumstances. They’re also lustrous (shiny) and quick to respond.

Chemical Properties of the group 1 elements on the periodic table

The electron configurations of alkali metals are shown in the table.

Chemical properties that are similar

• All alkali metals have chemical properties that are similar.

• This is due to the fact that alkali metal atoms all contain one valence electron

Reactivity

Alkali metals have a high level of reactivity.

Although alkali metals have similar chemical characteristics, their reactivity is different.

When you go below the Group, the reactivity of alkali metals increases.

[ Li   Na   K  Rb  Cs  Fr ]  More reactive

 The ease with which an alkali metal’s atom loses its single valence electron to achieve a stable noble gas electron arrangement is used to determine its reactivity (duplet or octet electron arrangement).

   Li      > >     Li+ +.   e- 

               (2.1)              (2)

     Na   >>        Na+ + e- 

            (2.8.1)            (2.8)

         K          >>         K +    + e-

            (2.8.8.1)       (2.8.8)

 The easier it is for an alkali metal atom to release its single valence electron, the more reactive it is.

Explanation:

 The following is an explanation for the increase in reactivity of alkali metals as they progress through Group 1.

• One valence electron exists in all alkali metals.

• During a chemical reaction, each atom of an alkali metal will release one valence electron, resulting in a stable duplet or octet electron configuration. As a result, a +1 charge ion is generated.

• The atomic size of alkali metals grows as you move below Group 1.

• More inner shells containing electrons screen the solitary valence electron as it moves away from the nucleus.

• This means that the single valence electron’s effective nuclear charge drops as the group number increases.

• The attractive forces between the nucleus and the single valence electron weaken as a result, and the nucleus pulls the single valence electron more weakly

• As a result, moving down the group allows the solitary valence electron to be liberated more easily.

• As a result, alkali metal reactivity rises as the group progresses.

As reducing agents

• In chemical processes, reducing substances are good electron suppliers.

• Because the solitary valence electron in each alkali metal atom may be easily liberated to achieve a stable electron arrangement of a noble gas, alkali metals are good reducing agents (good electron donor).

• When descending down Group 1, the strength of alkali metals as reducing agents increases.

[Li   Na  K  Rb  Cs  Fr ]  Stronger Reducing Agent

• This is because as you move down the group, the single valence electron of the alkali metals becomes much easier to liberate.

Chemical Properties of the Group 2 elements on the Periodic table

 This subsection discusses the key aspects of alkaline earth metal compounds as well as their general characteristics.

Hydrides

 Beryllium does not react immediately with hydrogen. The reduction of beryllium chloride with lithium aluminium hydride produces beryllium hydride.

 2BeCl2 + LiAlH4 → 2BeH2 + LiCl + AlCl3

Covalent hydrides, which have two metal atoms bonded to each hydrogen, are produced by Beryllium and Magnesium. A molecule known as a “banana Bond” is one in which three centres share only two electrons.

 When calcium, strontium, and barium react with hydrogen, metallic hydrides occur. Hydrides ions are produced by metallic hydrides.

 M + H2 → 2MH2 → M+ + 2 H–

 Hydrogen is released when hydrides react forcefully with water. Hydrogen is produced using a calcium hydride known as “Hydrolith.”

 CaH2 + 2H2O → Ca(OH)2 + H2

Reaction of Alkaline Earth Metals with Water

At high temperatures, beryllium doesn’t react with water. When magnesium combines with hot water, it only creates hydroxides and releases hydrogen.Magnesium is covered in an oxide layer that protects it from further water molecule damage.When other alkaline earth metals react with even cold water, they produce hydrogen.

Carbides

 Alkaline earth metals and their oxides, with the exception of beryllium, react with carbon to generate carbides. Carbides are employed as a source of acetylene gas because they react with water to produce it.

 M + 2C → MC2 MC2 + 2H2O → M(OH) 2 + C2H2

Oxides

Beryllium only interacts with oxygen at temperatures above 600°C. Magnesium and strontium create oxides when exposed to oxygen, whereas barium forms peroxides.

 BeO and MgO, which are covalent oxides, are more so than ionic oxides. Other oxides are amphoteric, such as amphoteric beryllium oxide, weakly basic magnesium oxide, and basic calcium oxide, whereas others are basic.

Hydroxides

 Oxides react with water to generate hydroxides.From beryllium to barium, the basic constitution and thermal stability of hydroxides changes.

Carbonates and Bicarbonates

 When hydroxides come into contact with carbon dioxide, they form carbonates.

 M(OH)2 + CO2 → MCO3 + H2O

Bicarbonates are water soluble and only exist in solution. In water, carbonates are solid and insoluble. Carbonates’ solubility falls from Be to Ba. Carbonates dissolve into bicarbonates in the presence of carbon dioxide. From Be to Ba, the carbonates’ ionic nature and thermal stability improve.

CONCLUSION

The alkali metals’ reactivities grow as they progress through the group. This is due to a combination of two factors: alkali metal ionisation energies and atomization energies. Because the alkali metals’ first ionisation energy falls as they progress through the group, it becomes easier for the outermost electron to be released from the atom and participate in chemical reactions, increasing reactivity.