Peculiar behavior of lithium(Li)-A detailed overview


In this article, you will learn about the peculiar behavior of Lithium with explanation, properties, and nature of lithium, the difference between lithium and other alkali metals by professional author.

Lithium differs in many properties from other alkali metals. This difference from its group members is due to the following reasons.

a) The sizes of lithium atom and Li+ ion are very small as compared to the atoms and ions of other alkali metals.

b) Due to the very small size of Li+, it has a high charge density and high polarizing power. For this reason, it has a greater tendency to form covalent bonds.

c) Its ionization energy and electronegativity are the highest among its family members.

Difference of Lithium from other alkali metals

There are certain factors where lithium differs from other group members as follows…

1: Hardness

Lithium is harder and lighter than other alkali metals.

2: Melting and boiling points

The melting and boiling points of lithium are higher than those of alkali metals.

3: Melting of lithium

Lithium can be melted in dry air without losing its brilliancy.

4: Covalent bonds

Li has the tendency to form covalent bonds with electronegative atoms, while other atoms of this group make the ionic bonds.

5: Solubility of salts

Some of the salts of lithium such as LiOH, LiF, Li2CO3, and Li3PO4 are insoluble in water. On the other hand, the corresponding salts of other alkali metals are soluble in water.

6: Reactivity

Li is the least reactive metal among all the alkali metals due to its small atomic size.

7:Burning in air

When Li is burnt in the presence of air, it forms only normal oxides such as Li2O. The other family members of group I-A form peroxides and superoxides.

8: Formation of oxides

The normal oxides of lithium (Li2O) dissolves in water quietly, while the oxides of other alkali metals dissolve in water more energetically.

9: Reaction with water

Li reacts with water in a slow rate, while other alkali metals react with water violently.

10: Basic strength of hydroxides

LiOH is less soluble in water and is a weak base, while the hydroxides of other alkali metals like NaOH and KOH are highly soluble in water and are strong bases.

11: Stability of hydroxides of lithium

LiOH is decomposed at red hot forming Li2O . The hydroxides of other alkali metals sublime upon heating.

Stability of hydroxides of lithium
Stability of hydroxides of lithium

12: Stabilites of hydrides

LiH is more stable than the hydrides of other alkali metals.

13: Soluibilites of cholirides

LiCl is deliquescent and soluble in alcohol and pyridine. The chlorides of other alkali metals do not do so.

14: Heats of solutions of chlorides

LiCl has exothermic heat of solution, while the chlorides of Na and K have endothermic heat of solutions.

15: Hydrolysis of chlorides

LiCl can undergo hydrolysis but the chlorides of other alkali metals do not exhibit this property.

16: Reaction with N2, C, and Si

Li reacts with nitrogen, carbon, and silicon to give nitrides, carbides, and silicide.

For example,

Reaction of lithium with Carom. nitrogen and silicon
Reaction of lithium with Carom. nitrogen and silicon

17: Decomposition of lithium carbonates

Li2CO3 is decomposed on heating to form Li2O and CO2, while carbonates of other alkali metals are stable towards heat.

For example

Decomposition of lithium carbonates
Decomposition of lithium carbonates

18: Decomposition of nitrates

When LiNO3 is heated it gives NO2 gas, while the nitrates of other alkali metals simply give oxygen.

For example

Decomposition of lithium nitrates
Decomposition of lithium nitrates

19: Reaction with acetylene

When acetylene is passed over strongly heated Li, it does not produce lithium acetylide. Other alkali metals form the corresponding metallic acetylides.

Reaction of sodium with acetylene
The reaction of sodium with acetylene

20: Complex formation

Lithium forms stable complex compounds. One of the stable complexes formed by lithium is Li(NH3)4.

Comparison of lithium with other alkali metals

comparison of lithium with other alkali metals
comparison of lithium with other alkali metals