Group 7 Properties

Question 1

State and explain the trend in group 7 melting/boiling points

Answer 1

Increases because:

• Halogens exist as non-polar diatomic molecules
• Weak van der waals forces exist between the molecules (IMF’s) which are broken when boiled/melted
• Induced dipole forces become stronger down the group as Mr increases this is because more electrons involved in the induced dipoles

Question 2

State and explain the trend in group 7 electronegativity

Answer 2

Decreases because:

• Shielding increases
• Effective nuclear charge decreases
• Decreases its ability to attract a bonding pair of electrons
  e. g. fluorine can form a stronger dipole than iodine

Question 3

What state is fluorine in at room temp?

Answer 3

Gas

Question 4

What state is chlorine in at room temp?

Answer 4

Gas

Question 5

What state is bromine in at room temp?

Answer 5

Liquid

Question 6

What state is iodine in at room temp?

Answer 6

Solid