Saturday, October 6, 2007

Chemistry Question - Periodic Table

Question from a Top School 2007 Prelim Paper:

Q) Astatine is a Group VII element below Iodine in Periodic Table. Which of the followingf statements concerning Astatine is correct?

A) It is a liquid at room temp and pressure.
B) It is a stronger oxidizing agent than iodine
C) It reacts with sodium ti form an ionic compound
D) Its diatomic molecules are held together by weak covalent bonds

Should be a mangeable question. Enjoy doing!

Learning Experience with A Difference


lijun(: said...

i think the answer is C.

since it's below iodine, it should be a solid at rtp. so it can't be A.

also, the higher the halogen in the group, the more reactive it is. so iodine should be a stronger oxidizing agent than astatine. so it's not B.

it's diatomic molecules are held together by weak van der waals forces, not weak covalent bonds. thus not D.

since it's in group VII, its ion has a charge of -1. thus will form ionic compound with sodium, which has a charge of +1. forming NaAt.

Anonymous said...

C. Sodium is a metal and astatine is a non metal (under halogens group) so they go through ionic bonding to form ionic compounds.

I'm not sure about A, so I left it out first.

B)Iodine is more reactive than Astatine, this makes it a stronger oxidising agent. I'm not sure whether this theory is right.

D)It is a diatomic molecule, but covalent bonds are strong. It's the intermolecular forces of attraction that are weak.

So by comparison, C sounds like a more logical answer than A. Do correct me if I'm wrong though.

Sean Chua said...

Well Done Lijun and Anonymous.
Answer is indeed C.

Keep up the good work!

Chem Prac in two days time.
All the Best!

"Learning Experience with A Difference"