How are Ralph's, Piggy's and Jack's personalities shown in Chapter 2?

Ralph is seen as a leader by most of the boys. He holds the "trumpet thing" (conch) and had a traits attributed to an adult:

You could see now that he might make a boxer, as far as width and heaviness of shoulders went, but there was a mildness about his mouth and eyes that proclaimed no devil."

Jack is aggressive and domineering.

Piggy is intelligent but seen as fat and a person to be victimized.