As we have noticed before, the Germans have the capability to make simple things a lot more difficult. The negation is actually no exception from this rule. If you might wonder what can be done difficult in saying NO, well then have a look at these phrases.

Ich esse den Apfel nicht. = I do not eat the apple. Ich habe kein Geld. = I do not have money.

What actually is the reason that we can't say:

INCORRECT: Ich habe Geld nicht. = I do not have money.

Let's check some other examples to see what actually the difference is:

Ich lese dieses Buch nicht. = I do not read this book. Ich lese keine Bücher. = I do not read books.

Ich gebe ihm das Buch nicht. = I do not give him the book. Ich gebe ihm kein Buch. = I do not give him any book.

There are four sentences and two are negated with nicht and two with kein. Let's see whether we find a rule for the German way (because however weird it seems to you there is no way of changing or ignoring it).