There is a lot of information contained in the
periodic table, some of which we will come
to later in the course. For now, we need
only concern ourselves with a few interesting
elements: carbon, nitrogen,
oxygen, and iron.
You'll hear a lot about these elements ---
especially, H, C, O, and N --- this semester.
In fact, these elements are so important
for astrobiology that collectively they
have been given a name: CHON.