How do I deliver my answer about silicons atomic mass?
Hi! I think you are asking about the labels. Atomic mass is how much the atom weighs. In your first case, 28.0855 au, the au stands for Atomic Units. One atomic unit is ROUGHLY the mass of one proton or neutron. For silicon, the mass of the particular combination of all of the protons and neutrons that form silicon add up to 28.0855 atomic units. Atomic Units are nice because you can just talk straight about the mass (remember, it’s a mass so small that you can’t easily measure it), and not have to connect it to a whole bunch of atoms or molecules forming up a mole that you can actually measure in real life. But the truth is, most of the time you are going to have to use measurements that you get in real life. So let’s talk about moles, then. The other mass you ask about, 28.0855(3)g mol-1, relates the mass in terms of grams per mole. In fact, g mol-1 is just a mathematical way of saying grams divided by moles, or grams per mol. A mole is 6.0221415 × 10^23 atoms (or molecules). That’s
