# Why NaCl does not conduct electricity in solid state?

1. Jun 17, 2014

1. The problem statement, all variables and given/known data
The title

2. Relevant equations
Nah

3. The attempt at a solution
It has no free moving ions or electrons

Then, my teacher saw the electrons and gave 0 marks to the question(It was on the test paper)

He said that if he didn't see electrons there, he would have given a mark.
Why? I don't understand.

If it does not have free moving ions but have free moving electrons, then it will conduct. My answer should not be wrong!

2. Jun 17, 2014

### Staff: Mentor

I don't see problem with electrons being mentioned, quite the opposite - it looks quite OK to me.

That is, your wording can be slightly confusing. If what you mean is that NaCl crystal has no free moving ions nor free moving electrons, I would accept it. Delocalized, freely moving electrons in the conduction band are what makes solids conductive.

I will move the question to physics forum, as it is better suited there.

3. Jun 17, 2014

Isn't that the same thing?
Can a native English speaker help me here?What do you think?

4. Jun 17, 2014

### dauto

The way you wrote it it might be possible to interpret as you stating that NaCl doesn't have electrons which isn't true. I think your meaning is clear by context though.

5. Jun 17, 2014

Yeah, I think he read the sentence separately:
[It has no free moving ions] [or electrons]

I think it's better to write:
[It has no free moving ions] nor [free moving electrons]. This makes more sense

6. Jun 17, 2014

### Staff: Mentor

When formally dissected, your answer states (among other things) "it has no electrons". Your adjective "free moving" is associated with ions. If you intend the adjective to also be associated with electrons then the adjective must be repeated, as Borek illustrated.

http://physicsforums.bernhardtmediall.netdna-cdn.com/images/icons/icon2.gif [Broken] Remember, an examination doesn't test a student's understanding, it tests a student's skill at convincing the examiner of his understanding.

Last edited by a moderator: May 6, 2017
7. Jun 17, 2014