Extensive properties, as volume and mass, depend on the amount of material. So, you can have a sample of gold and a sample of copper with the same volume as long as you have different amount of each one.
On the other hand, intensive properties do not depend on the amound of material but on the chemical constitution of the material. Density is an intensive property, so gold and copper have different densities. That is why you can use intensive properties to characterize different materials.
Answer is: MgF₂, magnesium fluoride.
Magnesium fluoride is salt, ionic compound, because magnesium is metal from 2. group of Periodic table of elements and has low ionisation energy and electronegativity, which means it easily lose valence electons, fluorine is nonmetal with greatest electronegativity, which meand it easily gain electron, so magnesium cation (Mg²⁺) and fluorine anion (F⁻) are formed.
The periodic table increases as you read left to right so it is A.
17.6667 Feet is the answer.
