Question

Match the molecules with their correct geometry.

• A. Linear
• B. Tetrahedral
• C. Trigonal planar

Answer 1

$\bullet$ According to VSEPRT, in a molecule repulsion between electron pairs follow the order:
lone pair - lone pair > lone pair - bond pair > bond pair - bond pair.

$\bullet$ In ${\text{BeCl}}_2$, there are two bond pairs on the central atom. To minimise the bond pair-bond pair repulsion, the shape will be linear.

$\bullet$ In ${\text{AlCl}}_3$, there are three bond pair on the central atom. To minimise the bond pair-bond pair repulsion the shape of will be trigonal planar.

$\bullet$ In ${\text{NH}}_3$, the central atom has three bond pair and one lone pair. To minimise the repulsion between bond pair-bond pair and bond pair-lone pair, the shape of molecule will be tetrahedral.

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