Jennifer Gordon of Alexandria has been named one of the winners in the National Symphony Orchestra's 1985 Young Soloists' Competition, sponsored by the McGraw-Hill Foundation Inc. Gordon, a violinist, was a winner in the high school division of the competition. A June graduate of the former Fort Hunt High School, she is a freshman at the Indiana University School of Music.

As a winner, Gordon performed as a soloist with the National Symphony Orchestra in a non-subscription concert. She also will have the chance to perform on WGMS radio in a full-length recital.

Gordon has appeared with orchestras performing at the Kennedy Center, Wolf Trap, the Smithsonian Institution, Constitution Hall and Blair House. She also attended the International Festival in Sofia as a guest of the Bulgarian government. Sheriff 'Adopts' School

The Alexandria sheriff's office recently "adopted" George Mason Elementary School, and staff members will volunteer their time to tutor students and provide tours of the courthouse and the correctional center. Speaking at a recent ceremony at the school in celebration of the partnership were Sheriff James Dunning, Robert W. Peebles, superintendent of schools; Marvin Maygarden, principal of George Mason; Lynnwood Campbell Jr., a school board member; Margaret Macensky, president of the George Mason P.T.A.; Marjorie Louis, a reading specialist at George Mason, and Steve Dawson, a sixth grader and the school's student body president. Optimists Honor Essayists

Edward Prados, a senior at Bishop Ireton High School, recently won the Optimist Club of Alexandria's annual essay contest. High school students were invited to submit essays on the topic, "Freedom: Our Most Precious Heritage." Ireton senior David Masri was awarded second place, and a third place award went to Ireton sophomore Robert Coleman.

Prados also placed third in the Optimist's district competition. Essays from 527 students in Virginia, Maryland, the District of Columbia and part of West Virginia were considered in the district competition. Students Win Speech Contest

Bridget Reeder, a student at T.C. Williams High School and a member of the school's Forensics League, placed first in the poetry interpretation category in the Northern Virginia Speech League district competition. T.C. Williams student Chris Francoise placed second in the same category. The students' forensics league coaches are teachers Flo West and Laurie Hinners.