Question

diagonal relationship btw aluminium and Sl

Answer 1

Dear Student,
The diagonal relationship exists between

1. Beryllium and aluminium
2. Between Boron and Silicon

The Reason of diagonal relationship is because On moving across the period and down the group there are opposite effects. On moving across the period the atomic size decreases while on going down the group the atomic size increases and most of the chemical properties are dependent on the atomic size therefore the elements that are diagonally present are closely related to each other.

DIAGONAL RELATIONSHIP BETWEEN Be AND Al

• Be²⁺ and Al³⁺ have almost same and smaller size and thus favour for covalent bonding. Both these form covalent compounds having low melting point and soluble in organic solvent.

• ​ The standard oxidation potential of both the metals are same (Be²⁺=1.69 volts, Al³⁺=1.70 volts).

• Both metals become passive to the attack of acids

• The oxides of metals (BeO ,Al₂O₃) are amphoteric in nature
• Both metals form stable complexes (BeF_​3^- , AlH₄^-)

​​DIAGONAL RELATIONSHIP BETWEEN B and Si

• Both are non- metals and exist in allotropic forms.
• Both have high mp and are semiconductor
• Both B and SI form volatile hydrides like boranes and silanes
• Both form only covalent compounds
• The chlorides of both boron and silicon are easily hydrolyzed by water

Regards!

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