In unserem Gruppenchat sammeln wir neue Wörter und kurze Fragen zum Kurs.

Because in here describes a location: in our group chat.

When in means in/inside a place (location), it takes the dative case.
Gruppenchat is masculine: der Gruppenchat.

So:

• der Gruppenchat → nominative
• in dem Gruppenchat → dative
• in unserem Gruppenchat → dative with the possessive unser

The ending -em on unserem shows masculine/neuter dative singular.

German main clauses usually put the finite verb in second position.

Here, the first position is taken by the phrase:

In unserem Gruppenchat

So the verb must come next:

In unserem Gruppenchat sammeln wir ...

That is why wir comes after sammeln.

Compare:

• Wir sammeln neue Wörter ...
• In unserem Gruppenchat sammeln wir neue Wörter ...

Both are correct. The second one emphasizes the setting first.

Yes. German very often combines nouns into compound nouns.

So:

• Gruppe = group
• Chat = chat
• Gruppenchat = group chat

This is completely normal in German. English often writes these as separate words, but German usually joins them into one word.

Other examples:

• Hausaufgabe = homework
• Sprachkurs = language course
• Wörterbuch = dictionary

Because German often leaves out the article when talking about things in general or some plural items.

So:

• wir sammeln neue Wörter = we collect new words
• wir sammeln kurze Fragen = we collect short questions

This is similar to English, where you can also say:

• We collect new words
• We collect short questions

If you added articles, the meaning would become more specific:

• die neuen Wörter = the new words
• die kurzen Fragen = the short questions

Because these are plural accusative noun phrases without an article.

The verb sammeln takes a direct object in the accusative:

• neue Wörter
• kurze Fragen

When there is no article, the adjective has to carry more grammatical information itself. In the plural accusative, that gives:

• neue Wörter
• kurze Fragen

This is part of German adjective declension.

A useful comparison:

• die neuen Wörter → with article, adjective becomes -en
• neue Wörter → without article, adjective is -e

They are in the accusative plural because they are the direct objects of sammeln.

The sentence answers the question What do we collect?

We collect:

• neue Wörter
• kurze Fragen

So both are objects of the verb.

You can think of the structure like this:

• sammeln = to collect
• wir sammeln was? = what do we collect?
• neue Wörter und kurze Fragen

Yes, both Wörter and Worte exist, but they are used differently.

• Wörter = individual words, vocabulary items
• Worte = words in the sense of utterances, statements, memorable words

In a language-learning context, neue Wörter is the normal choice because it means new vocabulary words.

Examples:

• Ich lerne neue Wörter. = I’m learning new words.
• Seine Worte waren freundlich. = His words were kind.

So in this sentence, Wörter is exactly what you would expect.

zum is a contraction of:

zu dem → zum

This is very common in German.

So:

• zum Kurs = zu dem Kurs

The preposition zu takes the dative case, which is why dem appears in the full form.

Common contractions like this include:

• am = an dem
• im = in dem
• vom = von dem
• zum = zu dem

In Fragen zum Kurs, the phrase means something like:

• questions about the course
• questions related to the course

Here zu does not mean physical movement to the course. It often means concerning, on the topic of, or related to.

So:

• eine Frage zum Kurs = a question about the course
• Informationen zum Test = information about the test
• Tipps zur Grammatik = tips on grammar

Notice that zur is zu der.

Yes. Grammatically, kurze describes Fragen.

So the phrase means:

• short questions

That suggests brief or simple questions, not long complicated ones.

If you wanted to say something like questions in short form, German would usually phrase that differently. In this sentence, the straightforward reading is simply that the questions are short.

Because neue Wörter and kurze Fragen zum Kurs are joined by und.

The structure is:

• In unserem Gruppenchat = where?
• sammeln wir = what do we do?
• neue Wörter und kurze Fragen zum Kurs = what do we collect?

The phrase zum Kurs most naturally belongs to Fragen, so the meaning is:

• new words and
• short questions about the course

Not usually:

• new words about the course and short questions

So the grouping is:

neue Wörter + kurze Fragen zum Kurs

Yes, absolutely.

Both are correct:

• In unserem Gruppenchat sammeln wir neue Wörter und kurze Fragen zum Kurs.
• Wir sammeln in unserem Gruppenchat neue Wörter und kurze Fragen zum Kurs.

The difference is mainly focus and style.

• Starting with In unserem Gruppenchat emphasizes the place/context.
• Starting with Wir is more neutral and straightforward.

German is flexible about what comes first, but the finite verb still stays in second position in a main clause.