Answer:
1, 2, 2, 1
Step-by-step explanation:
This is basically the equation we're trying to balance:
Cu + AgNO₃ → Ag + Cu(NO₃)₂
We start with Copper (Cu): There is 1 atom on the reactants'(left) side and 1 atom on the products'(right) side which means it's balanced
The second is Silver (Ag): There is 1 atom on the reactants' side and 1 atom on the products' side which means it's balanced
The third is Nitrogen (N) and there is 1 atom on the reactants' side and 2 atoms on the products' side. We balance it by multiplying the reactants' side by 2
Cu + 2AgNO₃ → Ag + Cu(NO₃)₂
Silver is now imbalanced so we multiply the silver atoms on the product's side by 2
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂
If you count them now, the atoms on each side are the same number
1 Copper atom on each side
2 Silver atoms on each side
2 Nitrogen atoms on each side
6 Oxygen atoms on each side (2 sets of 3 oxygen atoms)
1Cu + 2AgNO₃ → 2Ag + 1Cu(NO₃)₂