C6

Question 1

Describe how London forces arise (3)

Answer 1

Uneven distribution of electrons (1)
Creates or causes instantaneous dipole (in a molecule) (1)
Causes induced dipoles in neighbouring molecules (1)

Question 2

Explain why a molecule of SF6 has an octahedral shape (2)

Answer 2

Sulphur has 6 bonded pairs (and no lone pairs) (1)

Electron pairs repel each other as far apart as possible (1)

Question 3

Define electronegativity (2)

Answer 3

The ability of an atom to attract electrons (1 in a covalent bond (1)

Question 4

Predict the bond angle in an F2O molecule. Explain your answer (3)

Answer 4

104.5 degrees
2 bonded pairs and 2 lone pairs
Lone pairs repel more than bond pairs

Question 5

Explain why water has polar molecules but carbon dioxide has non polar molecules (2)

Answer 5

CO2 is symmetrical / H2O is not symmetrical

In CO2 dipoles cancel / In H2O dipoles do not cancel

Question 6

Shape of SF3 plus explain (3)

Answer 6

UP TO DATE OCR

1. shape of molecule - trigonal planar (1)
2. number of bonded regions - C has 3 electron dense regions or bonding regions (1)
3. Electron pair repulsion - electron pairs / bonded pairs repel OR electron pairs move as far apart as possible (1)