Answer:
Silicon Dioxide is a compound usually referred to as Quartz, it's a crystalline sort of material that is commonly found and used for equipment and furniture (like tables for example). Their molecular geometry is of tetrahedral shape (how their bonds look like and such)
Gold is an element that is a transitional metal that is quite malleable (able to hammer it to sheets) and is ductile (can be made into wires). As you probably have guessed, gold is used a lot for jewelry due to its lustrous appearance, and the fact that it can't corrode as well as its rarity. Due to it not being able to corrode, it's pretty useful in circuitry as it requires less management unlike elements with higher electrical conductivity like copper or silver. However gold is pretty costly so it's not often relied on for technology and mostly just used for show instead.
N2 or nitrogen gas, may seem like a compound for people new to chemistry but is actually just a diatomic molecule, meaning they are composed of only 2 atoms. So elements that are diatomic are commonly found with only 2 atoms (Oxygen gas for example, or Hydrogen gas) Nitrogen is part of the "magnificent seven" (the elements which are diatomic". Nitrogen is essential for a lot of living things (aside from us), and since they are the most abundant material in our air (78% of air is Nitrogen), there's plenty of life growing.