Lithium shows diagonal relationship with ____.

CONCEPT:

Diagonal Relationship in the Periodic Table

• The diagonal relationship in the periodic table refers to the similarity in properties between certain pairs of diagonally adjacent elements in the periodic table.
• This relationship is observed due to similarities in ionic sizes, charge/radius ratio, and electronegativities of these elements.
• In the case of lithium, it shows a diagonal relationship with magnesium.

EXPLANATION:

• Lithium (Li) is the first element in Group 1 (alkali metals), while magnesium (Mg) is the second element in Group 2 (alkaline earth metals).
• The diagonal relationship arises because:
  • The atomic radius of lithium (Li) is similar to that of magnesium (Mg).
  • The charge/radius ratio of Li⁺ (ion of lithium) is similar to that of Mg²⁺ (ion of magnesium).
  • The electronegativities and ionization energies of lithium and magnesium are also comparable, leading to similar chemical behavior.
• Examples of similar properties between lithium and magnesium:
  • Both lithium and magnesium form nitrides directly when they react with nitrogen (e.g., Li₃N and Mg₃N₂).
  • Both form covalent organometallic compounds (e.g., organolithium and Grignard reagents).
  • Both their chlorides (LiCl and MgCl₂) are deliquescent and soluble in organic solvents like ethanol.

Therefore, lithium shows a diagonal relationship with magnesium.