Anata wa

こんにちは (Konnichiwa) ClaudiaR-sc5G, 

Thanks for your question!

It really depends on the situation. The word あなは (anata) "you" isn't rude, but it can come across that way depending on when you say it and who you say it to. 

Using あなた (anata) with strangers who you know nothing about is perfectly fine! A good example of this would be if someone dropped their wallet and you wanted to get their attention and let them know they'd dropped something:

これ　は　あなた　の　さいふ　です　か？ (Kore wa anata no saifu desu ka?) "Is this your wallet?"

あなた (Anata) can also be used as a term of endearment. Wives will often use it to show affection towards their husbands. In this context, it's similar to "honey" or "sweetie."

あなた (Anata) would however, be considered rude when talking to close friends or family. In this case, you should use the person's name, followed by the appropriate title, like さん (san) or ちゃん (chan):

やまだ　さん　は　いきます　か？ Yamada-san wa ikimasu ka? "(Will you) go, Yamada?"

If you use あなた (anata) to speak to friends or family, you might come across as sounding a little superior, and they might be offended! So, instead of saying あなた　は？ (Anata wa?), you should say the persons name followed by は (wa), like this:

やまだ　さん　は？ (Yamada-san wa?) "How about (you), Yamada?"

You can also leave あなた (anata) out when it's obvious from context. For example, if you were talking to your friend Yamada and wanted to know if he was going to the party, you would say:

パーティー　に　いきます　か？ (Pātī ni ikimasu ka?) "(Will you) go to the party?

You don't need to say あなた (anata) or やまだ　さん (Yamada-san) here, since it's obvious who you're asking about.

I hope this helped! Please let me know if you have any other questions!
べんきょう　を　がんばって　ください！ (Benkyō o ganbatte kudasai!)