RICHMOND, JULY 6 -- Richard Lee Whitley, a part-time house painter and handyman, was executed tonight for the brutal sex murder of his 63-year-old next-door neighbor, Phoebe Parsons, seven years ago in the Pimmit Hills area of Fairfax County.

Whitley, 41, was believed to be the first Fairfax County resident to die in Virginia's electric chair.

He was pronounced dead at 11:07 p.m., five minutes after the electricity was turned on, according to Dwight Perry, state Corrections Department operations officer. Perry said Whitley, who was attended by a prison chaplain until his execution, made no final statement.

Whitley's appeals ran out at 7:10 p.m. when the Supreme Court refused to block the execution, but Gov. Gerald L. Baliles, who rejected a clemency bid Friday, remained in his office at the Statehouse and kept a telephone line open to the penitentiary in the event of unexpected developments. Whitley was the second person executed in Virginia since Baliles became governor a year and a half ago.

The only dissenters to the Supreme Court decision, according to a court spokesman, were Justices William Brennan and Thurgood Marshall.

Last week, the Virginia Supreme Court and the 4th U.S. Circuit Court of Appeals denied Whitley's appeals for a stay.

Whitley attorney Timothy Kaine based his appeals on arguments that his client, who had an IQ of 75, was "insane" or "feebleminded" and should have been commited to a state hospital.

Tonight, Kaine told reporters before the execution: "Murder is wrong in the gulag, in Afghanistan, in Soweto, in the mountains of Guatemala, in Fairfax County . . . and even the Spring Street Peniten- tiary" here.

Whitley was convicted May 13, 1981, of what Fairfax Commonwealth's Attorney Robert F. Horan Jr. described as the "unbelievably brutal" slaying of the Pimmit Hills widow.

At the trial, a signed statement was introduced in which Whitley admitted to strangling Parsons, cutting her throat and sexually assaulting her with two umbrellas.

Although expert witnesses testified on appeal that Whitley had "organic brain dysfunction," Circuit Court F. Bruce Bach, who presided at the trial, ruled that there were no legal grounds for finding Whitley to be feebleminded.

Whitley offered no reason for the attack other than that he went on a two-week drug and alcohol binge after his wife left him.

Pimmit Hills is off Rte. 7 just inside the Capital Beltway. Many residents interviewed there today said they were unaware of the murder, which occurred July 25, 1980.

But one longtime resident, Margaret Brazas, recalled Parsons as "really a good woman, a church woman and a mother. This was a very brutal murder. She didn't deserve this."

In a telephone interview with a Richmond television station, Whitley said he was "ready to die. I know they're going to kill me."

He said he would have liked to have had the execution televised and to be put to death without a hood over his head to "let the people see exactly what facial expressions you have when they put the juice to you."

Whitley was the sixth person executed in Virginia, and the 81st in the nation, since the Supreme Court lifted the death penalty ban in 1978.

As in past executions here, rival crowds of protesters showed up outside the brick-walled prison. On one side were about 100 antideath-penalty demonstrators who held a candlelight vigil. On the other was a like number from the surrounding blue-collar neighborhood who jeered at the death penalty opponents.Staff writer Liz Lazarus contributed to this report.