Here are the words with different stress patterns from the provided lists:

1. **benefit** (A) has stress on the first syllable; the others do not.
2. **mention** (A) has stress on the first syllable; the others do not.
3. **become** (A) has stress on the second syllable; the others do not.
4. **popular** (A) has stress on the first syllable; the others do not.
5. **activity** (A) has stress on the second syllable; the others do not.
6. **children** (B) has stress on the first syllable; the others do not.
7. **happy** (B) has stress on the first syllable; the others do not.

Overall, the words “volunteer,” “purpose,” “patient,” “hospital,” “encouragement,” “garden,” and “around” have different stress patterns, while the others generally follow a pattern of first or second syllable stress.