Just so you know, there are approximately 100 elements out there (that we know of at least). All 100 elements are shown in the periodic table, however only 92 of these elements occur naturally on Earth.

This is because the other, heavier elements in the periodic table have to be made artificially and they may exist only for a very short time before decaying into lighter elements. Sucks to be them, basically.

You should also know that elements are substances that are made up of only one sort of atom. Elements are shown in the periodic table, and can be divided into metals and non-metals.

Another crucial point? The atoms of each element are represented by chemical symbols. For example O represents an atom of Oxygen, and Na represents an atom of Sodium.