German contrastive connectives split into three groups by the word order they force. Obwohl and während are subordinating, so the verb goes to the very end of their clause. Trotzdem, jedoch and dennoch are adverbs: when they open a sentence, the verb still comes second, so the subject moves behind it. Aber and denn sit outside the sentence and change nothing.
Examples
- Obwohl es teuer ist, kaufe ich es.
- Although it's expensive, I'm buying it.
- Es ist teuer. Trotzdem kaufe ich es.
- It's expensive. I'm buying it anyway.
- Ich kaufe es, aber es ist wirklich teuer.
- I'm buying it, but it's really expensive.
- Die Technik hilft uns; sie schafft jedoch neue Probleme.
- Technology helps us; however, it creates new problems.
The mistake to avoid
Treating trotzdem and deshalb like English 'so' - they take position one, so you must invert: "Trotzdem kaufe ich es", never "Trotzdem ich kaufe es".
Where this fits in
Gesellschaft & Meinung, German B2: Über abstrakte gesellschaftliche Themen diskutieren und Argumente vorbringen — mit Konnektoren, formellem Register und Mitteln zur Meinungsäußerung.