Given a Silicium atom with $1s^22s^22p^63s^23p^2$ I have to write down all possible term symbols.
The solution says a possibility - apart from $^1S$, $^1D$ and $^3P$ - would be $^1P$, which - due to the Pauli principle - does not exist.
And here is my question: Why does $^1P$ not exist? Is there an easy way to see why $^1P$ can not exist, just by looking at the term symbol? Or maybe more general: Is there a way to look at possible term symbols and immediately say whether they can exists or not?
(I don't know much about theoretical quantum mechanics, the question was part of an experimental physics exam.)