9701 MCQ Solution 35

Question 35: [Inorganic > Group 7]:

The element astatine lies below iodine in Group VII of the Periodic Table.

What will be the properties of astatine?

1 It forms diatomic molecules which dissociate more readily than chlorine molecules.

2 It reacts explosively with hydrogen.

3 It is a good reducing agent.

Reference: Past Exam Paper – November 2002 Paper 1 Q35

Solution 35:

Answer: D.

Astatine is a larger atom than chlorine. When it forms a diatomic molecule it will have a greater distance between atoms thus will be weaker and disassociate more readily, hence 1 is correct. 

As the lowest halogen on the periodic table it is the least reactive, thus will not react explosively with hydrogen. 

Since 2 is incorrect 3 must be incorrect and the only valid option is D.