An element is a pure substance which is composed of only one
kind of atom.
The periodic table provides an organization of all of the
known elements. I'll expect you to memorize the first twenty
element (know their name and symbol) and a number of common
elements. I'll also expect you to know the phase of every element
in the periodic table.
What does an element look like? If it consists only of atoms
we could use a single circle/sphere (
), if it consisted of molecules with two
atoms it would look like (
). One element has eight atoms in the molecule. That
element is sulfur and a sulfur molecule would look like;
![](STLec15.gif)
The formula of the element sulfur is S8.