NEET2026ChemistryClassification of Elements and Periodicity in PropertiesActual
The correct statement is
Options
- AAluminium has five valence orbitals.
- BBoron has a maximum covalency of four.
- CBeryllium has three valence orbitals.
- DMagnesium has a maximum covalency of four.
Correct answer
B. Boron has a maximum covalency of four.
Step-by-step solution
The electronic configuration of Boron (atomic number 5 ) is 1s² 2s² 2p¹ . Its valence shell is the second shell ( n=2 ), which contains one 2s orbital and three 2p orbitals, giving a total of four valence orbitals. Due to the absence of d -orbitals in its valence shell, Boron cannot expand its octet and has a maximum covalency of four (e.g., in [BF₄]⁻ ). Aluminium ( n=3 ) has one 3s , three 3p , and five 3d orbitals in its valence shell, making a total of nine valence orbitals. Beryllium ( n=2 ) has one 2s and thre