Question

a student tested a sample of carbon (c) by combining it with water. there was no reaction between the carbon and water. the student concluded that carbon must be a group 18 element, since it was unreactive. is this conclusion correct? why or why not?
no. the carbon probably did react, but did not give off any signs or indications of a chemical change.
no. just because carbon did not react with water, does not mean it wouldnt react with a different compound.
yes. the student can make a reasonable conclusion based on one experiment.
yes. water would react with almost every element, except group 18 elements.

Explanation:

The reactivity of an element depends on the substance it reacts with. Just because carbon didn't react with water doesn't mean it's unreactive in general or a Group 18 element. Group 18 elements are noble gases with very low reactivity, but carbon is a Group 14 element. One - experiment with water is not enough to classify carbon as a Group 18 element.

Answer:

B. No. Just because carbon did not react with water, does not mean it wouldn't react with a different compound.