Answer:
See below
Explanation:
The equation shows Al / Cl = 2/3 or 3/2 Al = Cl
3/2(20) = 30 Cl atoms needed
The equation shows a one-to-one relationship between Al and AlCl3
produced so if you use 20 Al atoms you get 20 AlCl3 molecules
The mass of an atom comes from
the protons and neutrons that are found in the nucleus. The number of protons
is the atomic number of an element. To find the number of neutrons, subtract
the atomic number from the mass of an atom. So, if an element is 76, the number
of protons AND electrons is also 76.