Te reacts with F2 at 150 °C to form TeFx. Molecules of TeFx are octahedral with bond anglesof 90°.Explain why TeFx is octahedral with bond angles of 90°.................................................................................................................................................................................................................................................................................................................................................................................................................................................... [2]

The shape of a molecule is determined by the number of bonding pairs and lone pairs of electrons around the central atom. This is known as the VSEPR (Valence Shell Electron Pair Repulsion) theory.

In the case of TeFx, tellurium (Te) is in the 16th group of the periodic table, meaning it has 6 valence electrons. Fluorine (F), being in the 17th group, has 7 valence electrons. When Te reacts with F2, it forms a compound where Te is the central atom surrounded by F atoms.

Since Te has 6 valence electrons, it can form 6 bonds with F atoms. This results in an octahedral shape, which is one of the geometrical shapes predicted by the VSEPR theory for molecules with six pairs of electrons in the valence shell of the central atom.

The octahedral shape has bond angles of 90° because in an octahedron, the repulsion between the electron pairs is minimized when the pairs are as far apart as possible, which happens at an angle of 90°.