molecules - Why is O2 enough to form a mole of Oxygen?

I understand that this is the most basic knowledge of moles, however I'm still unsure - according to easy research, $\ce{O2}$ forms a mole of Oxygen. As a mole is $6.022*10^{23}$, exactly what on the periodic table can we use to find out that it's 2 Oxygen in one mole? Wouldn't it be $6.022*10^{23}$, instead of 2?

Answer

$\rm O_2$ is the most common form of oxygen---the periodic table won't really tell you that.

Avogadro's number tells you how many particles there are in a mole.

There are $6.022\times 10^{23}$ O atoms in a mole of O atoms.

There are $6.022\times 10^{23}$ $\rm O_2$ molecules in a mole of $\rm O_2$.

Since you have 2 oxygen atoms in one $\rm O_2$ molecule, there are $2\times 6.022\times 10^{23}$ O atoms in a mole of $\rm O_2$.

Do you see the difference?