Naming the constant
The same number has now turned up over and over across two pages. A number like that has earned a name.
The Avogadro constant
In honour of the great scientist Amedeo Avogadro, this constant number is called the Avogadro constant. The symbol used for it is L.
L = 6.022 × 1023
What does it count?
L is not a mass and not a volume — it is simply a count. Just as a dozen is 12, it is a number of particles and nothing more. Which is why it carries no unit either.
| What you take | How many particles are in it |
|---|---|
| The relative atomic mass in grams | L atoms |
| The relative molecular mass in grams | L molecules |
| The formula mass in grams | L formula units |
One thing still has no name
Writing "6.022 × 1023 particles" every time is awkward. The amount itself needs a name — and section 7.4 is where it gets one.