Topic 12: Group 17 Halogens.

Question 1

What is another name for Group 17 elements?

Answer 1

Group 17 elements are also known as halogens.

Question 2

What are the molecular forms and bonding in Group 17 elements at room temperature?

Answer 2

Group 17 elements are non-metals that exist as diatomic molecules (e.g. F₂) at room temperature. Each molecule has a single covalent bond between the two atoms.

Diatomic refers to a molecule consisting of two atoms.

Question 3

What are the physical states and colors of Group 17 elements at room temperature?

Answer 3

• Fluorine: Pale yellow gas.
• Chlorine: Green gas.
• Bromine: Orange-brown liquid.
• Iodine: Grey solid (purple vapour).

Question 4

How does the atomic radius of Group 17 elements change as you go down the group?

Answer 4

The atomic radius increases down Group 17 due to the addition of extra electron shells which outweighs the effect of increasing nuclear charge, resulting in a larger atomic size.

Question 5

How does the melting and boiling point of Group 17 elements change as you go down the group?

Answer 5

The melting and boiling point of Group 17 elements increases down the group due to stronger intermolecular van der Waals forces, specifically instantaneous dipole-induced dipole interactions. As the size of the molecules increases, these forces become stronger, requiring more energy to overcome them.

Question 6

How does the volatility of Group 17 elements change down the group, and why?

Answer 6

The volatility of Group 17 elements decreases down the group because larger molecules have stronger intermolecular van der Waals forces (instantaneous dipole-induced dipole interactions). As these forces increase with molecular size, more energy is needed to overcome them, making the elements less volatile.

Volatility is the ease with which a substance evaporates.