Quiz on Group 7 (Halogens)

What type of reaction occurs when a more reactive halogen displaces a less reactive halogen?

• Decomposition reaction

• Displacement reaction

• Redox reaction

• Combination reaction

Answer explanation

A displacement reaction occurs when a more reactive halogen replaces a less reactive halogen in a compound. This is a characteristic behavior of halogens, demonstrating their reactivity differences.

Which halogen is a purple-black solid?

• iodine

• chlorine

• bromine

• fluorine

Answer explanation

Iodine is the only halogen that appears as a purple-black solid at room temperature. Chlorine and fluorine are gases, while bromine is a reddish-brown liquid.

What happens to the melting and boiling points of halogens as you go down the group?

• They fluctuate

• They increase

• They remain the same

• They decrease

Answer explanation

As you go down the group of halogens, the melting and boiling points increase due to the greater atomic size and increased van der Waals forces, which require more energy to overcome.

Which of the "Halogens" has yellowish green color?

• Chlorine

• Bromine

• Flourine

• Iodine

Answer explanation

Chlorine is the halogen that appears as a yellowish-green gas at room temperature. In contrast, bromine is a reddish-brown liquid, fluorine is a pale yellow gas, and iodine is a dark purple solid.

What is the electronic configuration of halogens?

• 5 electrons in the outer shell

• 7 electrons in the outer shell

• 8 electrons in the outer shell

• 6 electrons in the outer shell

Answer explanation

Halogens, found in Group 17 of the periodic table, have 7 electrons in their outer shell. This configuration makes them highly reactive as they seek to gain one more electron to achieve a stable octet.

Which halogen can displace iodine from potassium iodide?

• Bromine

• Fluorine

• Chlorine

• All of the above

Answer explanation

Chlorine is more reactive than iodine and can displace it from potassium iodide. Bromine can also displace iodine, but it is less reactive than chlorine. Therefore, the correct answer is chlorine.

Which halogen is the most reactive?

• Chlorine

• Bromine

• Fluorine

• Iodine

Answer explanation

Fluorine is the most reactive halogen due to its high electronegativity and small atomic size, which allows it to attract electrons more effectively than chlorine, bromine, or iodine.

What is the appearance of iodine at room temperature?

• Yellow gas

• Red-brown liquid

• Grey solid

• Pale green gas

Answer explanation

Iodine appears as a grey solid at room temperature. It is not a gas or liquid under these conditions, making 'grey solid' the correct choice among the options provided.

Which of the following halogens is a solid at room temperature?

• Fluorine

• Bromine

• Chlorine

• Iodine

Answer explanation

Iodine is the only halogen that is a solid at room temperature, while fluorine, chlorine, and bromine are gases or liquids. This property is due to iodine's larger molecular size and stronger van der Waals forces.

All halogens lose 7 electrons from their outer shell to become stable.

• true

• false

Answer explanation

The statement is false. Halogens have 7 electrons in their outer shell and typically gain 1 electron to achieve stability, not lose 7.