1. SOL 5.4D Study Notes
● Atoms are the basic building blocks of matter.
● A molecule is a group of two or more atoms that bond together. Atoms are the basic
building blocks of matter.
● A compound is a substance that is made of two or more elements that are bound together
chemically. There are millions of compounds around you right now – odds are, most
everything you see at this moment is a compound!
● When two or more chemicals combine to form a compound, you might see one of the
following happen:
o A new solid substance is created
o A new gas is created
o A new liquid is created
o Heat or light is created
o There is a color change
● The elements that combine to form a compound cannot be separated again.
● There are around 2 million different compounds that are formed from the elements on the
Periodic Table.
● Carbon can be found in more compounds than any other element.
● Some compounds have the same elements but can be very different substances. For
example, but CO (carbon monoxide) and CO2 (carbon dioxide) are made of carbon and
oxygen. Carbon monoxide has just one oxygen atom, while carbon dioxide has two. Both
are colorless gases, but carbon monoxide is deadly.
● Common compounds
Compound Name Chemical Formula
Water H2O
Table Salt NaCl
Rust Fe2O3
Carbon Dioxide CO2
Sugar C12H22O11
● What does a compound formula tell you:
○ How many elements are in the compound as well as how many of each are in it.
■ For example, the chemical formula for glucose is C6H12O6
● This tells you that there are 6 carbon atoms, 12 hydrogen atoms, and 6
oxygen atoms in one molecule of glucose
