Carbon-14 dating could be used to estimate the age of all of the following except
a. fossils
b. ancient scrolls
c. petrified wood
d. artifacts from the titanic ship

I would think artifacts from the titanic ship because carbon-14 is an isotope of carbon found in organic material. inorganic material therefore does not posses carbon- 14 and since all the other items are organic, only the artifacts could not be directly dated.

When dating inorganic material, organic material in the same surrounding sediment layer is usually used. In the case of the Titanic, there is no sediment layer. There is also the possibility that the ocean's salt water would skew any attempt at carbin dating but that is just a thought i am not sure about

Outermost (valence) electrons

The teacher is mostly talking about the distillation of a mixture