Alphonse (unlike his brother) is more pacifistic, gentle, and trusting. He cares deeply about his older brother, although he tends to be the voice of reason towards Ed's antic, the two sometimes bicker with each-other (due to their differences,) but he still loves him regardless.After the incident in Laboratory 5, he felt depressed about the fact that he may not be real and that if it's possible for him to get his body back, but afterwards he got out of his depression and returned back to normal.All in all, much of his personality was inherited from his mother.
Powers and Abilities
Alchemy - Like his brother, he too can perform alchemy by clapping is hands on a transmutation circle.Armor Body - but due to his soul being attached to an armored body, Alphonse doesn't require food, drink, or sleep nor does he get fatigued from running of lifting objects.Soul Transplantation - He is able to tranfer a piece of his soul into and armored body, due to him being bonded to one (Conqueror of Shamballa only.)
Alphonse has a fondness for cute animals (especially stray ones) and will try to adopt them, much to his brother's disdain.Unlike Ed (and if you want to count Envy from the 2003 anime,) he doesn't harbour no ill-feelings towards his father.