Dr. Thomas Penn, former vice-chairman of the Arlington County school board, was voted in as its chairman Friday at an annual organizational meeting of the board. He succeeds Diane Henderson, who had served as school board chairman for one year.

Mary Margaret Whipple, beginning her second year of a four-year term, was voted in as vice-chairman of the board.

Penn said he plans to concentrated on three areas as board chairman: the smooth reorganization of Arlington's secondary schools, the improvement of basic learning skills and adequate funding of the school budget.

Penn, a management education program coordinator at the Postal Service Training and Development Institute, holds a bachelors degree from St. Paul's College and a masters and doctorate in education from American University.

He is a former member of the Arlington Planning Commission and a recent president of the Metropolitan Area Board of Education. He and his wife Marian have two children who are graduates of Arlington public schools.

Whipple holds a bachelors degree ion English from American University and masters in American literature from George Washington University. She is former chairman of the Arlington schools' Five Year Planning Committee.

The Arlington County school board chairman receives $3,500 a year and aother members receive $3,000.

The board usually meets at 7:30 p.m. on the first and third Thursdays of each month at the Arlington Education Center, 1426 N. Quicy St., Arlington.