Group 17 Flashcards Preview

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Flashcards in Group 17 Deck (11)
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1
Q

What is significant about the elements in group 17?

A

They are the first group to contain all non-metals.

2
Q

Why does F2 have unusually weak bonds?

A

It is small so there is lots of lone pair-lone pair repulsion, making the bond weaker than anticipated.

3
Q

How does bond strength of the diatomic covalent molecules change down the group?

A

They increase from F2 to Cl2 and then decrease down the group.

4
Q

What is the most common oxidation state?

A

-1.

5
Q

Why is the boiling point of HF low?

A

It has unidirectional H-bonding compared to H2O which has a 2D H bonding network. The H bonding is retained even when heating to 60 degrees. Not all of the hydrogen bonds need to be broken for the compound to boil, hence the low boiling point.

6
Q

Why is HF a weaker acid compared to those going down the group?

A

HF is a strong bond and there is ion pair formation betwen H3O+and F-.

7
Q

What oxidation state does F adopt?

A

0 or -1.

8
Q

What oxidation states can the halogens other than F adopt?

A

-1, 0, +1, +3, +5 and +7.

9
Q

What are the properties of the interhalogens?

A

The biggest atom is always the central one and they are all highly reactive.

10
Q

What does exergonic mean?

A

The formation enthalpy is less than zero.

11
Q

What is PTFE?

A

Telfon - polytetrafluroethylene.