ANGOLA, La. (AP) _ John Brogdon, who begged for mercy for torturing and murdering an 11-year- old girl because he was mentally retarded and a child abuse victim, was executed early Thursday in the electric chair.

Brogdon, 25, was pronounced at 12:12 a.m., said C. Paul Phelps, secretary of the Department of Corrections.

Brogdon, the seventh inmate executed in Louisiana since June and the second within a week, was calm but apprehensive as he was strapped into the chair.

He was led into the death chamber shortly after midnight and asked if he wanted to make a statement.

''God bless ya'll,'' was all he said.

The U.S. Supreme Court, Brogdon's last hope for evading Louisiana's electric chair a third time, refused Wednesday night on a vote of 6-2 to stay the execution.

Warden Hilton Butler at the Louisiana State Penitentiary said Brogdon spent his final hours with a religious adviser, Rabbi Myra Soifer.

The Louisiana Supreme Court, U.S. District Court, and the 5th U.S. Circuit Court of Appeals also refused this week to block the execution. The state Pardon Board also rejected arguments that Brogdon should be spared because he is mildly retarded and was abused as a child by his father.

Brogdon was condemned to die for the Oct. 7, 1981, rape and torture murder of Barbara Jo Brown, who was beaten with bricks, stabbed with broken bottles and jabbed with pointed sticks while she was raped.

His father, Ed Brogdon, admitted at the Pardon Board hearing to drinking and smoking marijuana with his teen-age son, and said he beat him so severely that he once broke some of the boy's ribs.

John Brogdon, described as an alcoholic since he was 14, said during the hearing he didn't think he deserved clemency, but, ''I would like to live.''

Shortly after his arrest, Brogdon, then 19, told officers how he and Bruce Perritt, 17, stabbed the girl and struck her on the head with a brick after repeatedly raping her near her Luling home.

According to trial testimony, the two teen-agers picked up the girl after she slipped away from home and went back to a convenience store where they had talked to her earlier. They drove around for more than an hour, and then went to drink beer on a Mississippi River levee where the murder occurred.

Perritt was convicted of first-degree murder but was automatically sentenced to life in prison when the jury could not agree on whether to recommend the death penalty.

Brogdon's lawyers argued the execution should be postponed until the Supreme Court rules in the fall whether juveniles convicted of murder can be executed. They said the two issues are related because they involve people too immature to fully understand the consequences of their actions.

They also argued that the execution should be postponed until the Supreme Court rules in the Leslie Lowenfield case, in which Louisiana's death penalty law has been challenged.

Lowenfield, scheduled to die earlier this year, won a postponement, but a similar argument failed to stop the execution last Friday of Willie Watson, convicted of the rape-murder of a Tulane University medical student.

Assistant District Attorney Greg Champagne of St. Charles Parish argued that although Brodgon might be somewhat mentally retarded, he knew right from wrong at the time of the murder and was mentally competent to stand trial.

Brogdon had execution dates set aside in 1982 and 1983.