"The man does not like groups."
Translation:Der Mann mag keine Gruppen.
I find it easier to remember if you think of "Der Mann mag keine Gruppen" as "The man likes no groups" or "The man likes (not any) groups" - using correct word order this becomes: "The man does not like any groups"
'Eine' is the (feminine/plural) article for 'a' 'Keine' is just the negated form, so you can roughly translate this by simply negating the article in English, thus 'a' becomes 'not a' or 'not any'
"The man likes none of the groups" is a different, more specific sentence - it would also be expressed differently in German.
To answer your question, the meaning is the same whether you say ...mag keine Gruppen or ...mag Gruppen nicht, with the main difference being simply the latter is not how Germans say it. Kind of like how "...likes no groups" is not grammatically incorrect English, but just sounds odd. Just treat it as something to remember - sometimes we need to learn different patterns of expression, beyond just word-for-word translations.
Well as far as I know there is nothing wrong about it, if you use the article before “Gruppen” . However, if you say “Der Mann mag nicht die Gruppen” you would need to complement with something like "...,sondern die Menschen”.
I think the equivalent in english wou be something like “The man likes not the groups, but the people” (I'm really not sure whether this sentence makes sense in english).
In german we can negate the hole sentence or parts of it.
1 - Nicht ich esse die Pizza, sondern meine Frau.
2 - Ich esse nicht die Pizza, sondern den Fisch.
3 - Ich esse die Pizza nicht
-st is the verb ending for "du"
eg. Du magst keine Gruppen = you don't like any groups.
Often, you simply need to take off the -st to get the he/she/it (er/sie/es) form, mag. Der Mann can be replaced with the pronoun er (he), so this is the form of the verb (conjugation) to use.
Duolingo's first tips page tells you when to use ein or eine (for masculine/neuter nouns, and for feminine nouns): https://www.duolingo.com/skill/de/Basics-1
The lesson on accusative case tells you when to use einen (for masculine nouns in accusative case): https://www.duolingo.com/skill/de/Accusative-Case
The usage of kein/keinen/keine follows these patterns, but instead of meaning "a/an" it means "no/not a/an".
It is plural:
Er mag keinen Hund. He doesn't like a dog.
Er mag keine Hunde. He doesn't like dogs.
Er mag keine Gruppe. He doesn't like a group.
Er mag keine Gruppen. He doesn't like groups.
Er mag kein Haus. He doesn't like a house.
Er mag keine Häuser. He doesn't like houses.
I have to disagree, Salomee. English "He doesn't like a group" means there is one specific group which he does not like. But German "Der Mann mag keine Gruppe" means he does not like any group. That equivalent to "he does not like groups", therefore it should be accepted. We don't learn to translate a sequence of words, we aim to understand and translate the sentence, right?