No, it's not unreasonable but all sorts of things can go wrong with emails, especially when busy people are sending/receiving so many. Think of the organization alone that an advisor would have to do with 8-10+ students; if he sucks at it. . .

I'd either call him and politely tell him you think there's something wrong with his email box because you haven't heard back from him and you've sent him a couple things or I'd drop by his office if you can and poke your head in and just ask, "did you get my emails?". Sometimes it takes multiple tries or a length of time, etc. depending on what's going on with a person.