I am taking an Earth Science course now and currently reviewing some basic chemistry knowledge needed for further study on earh mineral and rocks. But I haven't touched chemistry for almost 2 years that I start to forget things, can someone help and clarify some basic chemistry stuff? I would appreciate! :wink:
1) Are the terms "element" and "atom" interchangeable? If not, why not?
2) Do the terms "substance" and "matter" mean exactly the same thing?
3) "Two of the eight common elements in the earth's crust are oxygen (O) and silicon (Si)"
Why is oxygen expressed as O, instead of O2, in both the quote and diagram? Does that mean single O atom exist naturally in the crust?
4) Compound: a substance that results when the atoms of two or more elements are chemically combined
This is the definition of a "compound" from my text book and it's the same as all sources in the internet. According to the definition of a compound, O2 and N2 are not compounds, than what are they? elements?