Why is percival unable to remember his name and address?

Please help!! :(

He is one of the "littleuns". He is so traumatized by the events he lives through that he forgets what civilization is about, including his name.
http://www.bookrags.com/notes/lof/CHR.htm
"Percival Werthys Madison: This littlun would always give a full introduction of himself: 'Percival Wemys Madison. The Vicarage. Harcourt St. Anthony, Hants, telephone....' complete with address. He is one of the three attacked by rocks thrown by Roger and Maurice when building sand castles. By the end, when finally rescued by the grown-ups all he can say is 'I'm-- I'm--' before realizing he has forgotten his civilized identity. "

does ralph understand why he must be killed?

civilization has been wiped away as has the name and address that was in his head when he was a part of civilization

what is the irony of Samneric's behavior in Chapter 12

They allow Ralph to pass them in the forest without telling the others and then the next day they are part of "the hunt" to kill Ralph

comprehensive grasp of the significant ideas of the symbol

what is the exact quote from the novel that says when percival forgets his name?

He says:

"I'm–I'm..."

In the novel "Lord of the Flies," Ralph does not understand why he must be killed. Ralph is the main protagonist and the leader of the group of boys stranded on the island. As the story progresses, there is a power struggle between Ralph and Jack, who wants to be the leader himself.

Eventually, Jack becomes the leader of a group of boys who engage in savage and violent behavior. They hunt and kill animals and even begin to hunt Ralph. Jack and his followers believe that Ralph needs to be killed because he represents order, civilization, and the rules that they have chosen to ignore. They see Ralph as a threat to their newfound freedom and their descent into savagery.

Ralph, on the other hand, does not understand why he is being hunted and does not comprehend the extent of the violence that Jack and his followers are willing to commit. He represents rationality, responsibility, and a desire to be rescued from the island. He struggles to maintain order and unity among the boys but is eventually isolated and targeted for his attempts to keep some semblance of civilization.

Overall, Ralph's inability to understand why he must be killed reflects the loss of reason and the dark descent into savagery that the boys experience throughout the novel.