Do you need wudhu do read certain parts of the Quran? For example Ayatul Kursi and the last 3 surahs?

If you read something like Ayatul Kursi without wudhu as a dua, is it as effective?

I understand that when you recite Ayatul Kursi, Allah sends angels to protect you. Is there anything else which can affect the protection Ayatul Kursi can give, for example pictures/toys in the house?