Answer
The charge $q_1$ is the same as previously.
Work Step by Step
Initially, the potential difference across $C_1$ is equal to the battery voltage.
Then $C_2$ is added in parallel.
When two capacitors are in parallel, the potential difference across each capacitor is equal. The potential difference across each capacitor will be equal to the battery voltage.
Therefore, the potential difference across $C_1$ is the same as previously.
Note that in general: $~~q = C~V$
Since the potential difference across $C_1$ is the same as previously, the charge $q_1$ is also the same as previously.
