Answer:
Step-by-step explanation:
Na₂CrO₄
Types of atoms: Number of atoms
Na 2
Cr 1
O 4
Total = 3 Total = 7
3CaCl₂
Types of atoms: Number of atoms
Ca 3
Cl 6
Total = 2 Total = 9
NH₄C₂H₃O₂
Types of atoms: Number of atoms
N 1
H 7
C 2
O 2
Total = 4 Total = 12
4Al₂(CO₃)₃
Types of atoms: Number of atoms
Al 8
C 12
O 36
Total = 3 Total = 56