Well, let's look at the word.
so-cial
The word social has two syllables as you can see above.
How many syllables does 'astronaut' have?
Three (as-tro-naut).
Macmillan Dictionary for Children. Childcraft Dictionary. World Books, Inc. 1975. Print.
How many syllables does the word mean have?
The word "mean" has one syllable (IPA pronunciation: /miːn/).