* Na2CO3: This is the chemical formula for sodium carbonate. It tells us that each molecule contains:

* 2 sodium atoms (Na)

* 1 carbon atom (C)

* 3 oxygen atoms (O)

* 4 Na2CO3: This means we have 4 molecules of sodium carbonate.

Calculation:

1. Atoms per molecule: 2 Na + 1 C + 3 O = 6 atoms per molecule

2. Total atoms: 6 atoms/molecule * 4 molecules = 24 atoms

Answer: There are 24 atoms in 4 Na2CO3.