To determine the ratio of silver (Ag) to bromine (Br2) in the decomposition of silver bromide (AgBr), we start with the balanced chemical equation for the decomposition reaction:
\[ 2 \text{AgBr} \rightarrow 2 \text{Ag} + \text{Br}_2 \]
From the equation, we can see that 2 moles of AgBr decompose to produce 2 moles of Ag and 1 mole of Br2.
Thus, the ratio of silver (Ag) to bromine (Br2) produced is:
- Silver (Ag): 2 moles
- Bromine (Br2): 1 mole
So, the ratio of silver to bromine is:
\[ \text{Ratio} = \frac{\text{Ag}}{\text{Br}_2} = \frac{2}{1} \]
Therefore, the answer is 2:1.