3.5 AS Level

Shapes of molecules

9 flashcards to master this topic

Definition Flip

State the shape and bond angle of BF3.

Answer Flip

BF3 has a trigonal planar shape due to 3 bonding pairs and no lone pairs around the central Boron atom. The bond angle is 120°.

Definition Flip

State the shape and bond angle of CO2.

Answer Flip

CO2 is a linear molecule. The central Carbon atom has two double bonds to oxygen atoms, resulting in a bond angle of 180°.

Definition Flip

State the shape and bond angle of CH4.

Answer Flip

CH4 has a tetrahedral shape due to four bonding pairs and no lone pairs around the central Carbon atom. The bond angle is 109.5°.

Definition Flip

State the shape and bond angle of NH3.

Answer Flip

NH3 has a pyramidal shape due to three bonding pairs and one lone pair around the central Nitrogen atom. The bond angle is approximately 107°.

Definition Flip

State the shape and bond angle of H2O.

Answer Flip

H2O has a non-linear (bent) shape due to two bonding pairs and two lone pairs around the central Oxygen atom. The bond angle is approximately 104.5°.

Definition Flip

State the shape and bond angle of SF6.

Answer Flip

SF6 has an octahedral shape due to six bonding pairs and no lone pairs around the central Sulfur atom. The bond angle is 90°.

Definition Flip

State the shape and bond angles of PF5.

Answer Flip

PF5 has a trigonal bipyramidal shape. There are two bond angles present: 120° between the equatorial Fluorine atoms, and 90° between the axial and equatorial Fluorine atoms.

Key Concept Flip

Explain how VSEPR theory is used to predict molecular shapes.

Answer Flip

VSEPR (Valence Shell Electron Pair Repulsion) theory states that electron pairs around a central atom will arrange themselves to minimize repulsion. This arrangement determines the molecule's shape and bond angles. Lone pairs have greater repulsive force than bonding pairs, affecting bond angles.

Definition Flip

Predict the shape of the [BeCl2] molecule.

Answer Flip

The [BeCl2] molecule is predicted to be linear. There are two bonding pairs of electrons around the central Beryllium atom and no lone pairs, resulting in a bond angle of 180°.

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3.3 Metallic bonding 3.6 Intermolecular forces, electronegativity and bond properties