Are these places in Oakland, California safe?

We're visiting our family in Oakland, Cali and I've heard that certain parts of this city are unsafe just because of the gangs and such. I was wondering if Chinatown and around 13th street are safe. And if the Oakland International Airport area is safe as well. I'd feel better if I knew what to avoid. Please include what to avoid around these areas. I've never been there and want to feel safe.