It began at a Friday night teen-age rumble that left a 10th grader with shotgun wounds in the face and chest. Within a week of the shooting, five students at his high school were arrested for fighting. A baseball bat and two oriental skull crushers called nunchaks were confiscated, and a dozen police cars had invaded the campus to rescue an officer in distress.

The recent trouble at Groveton High School would alarm administrators in any school system. But in affluent Fairfax County, where bad news is usually no worse than a slight dip in College Board scores, the incidents during the last few weeks have been an unaccustomed shock.

"This kind of thing really isn't normal for Fairfax," says Sandra Duckworth, who represents the Groveton area on the County Board of Supervisors. "I'm not really sure what to blame it on."

Fairfax County advertises itself as devotedly middle class, suburban and secure from most urban stress. That stereotype is still largely true. But during the past decade, commercial development and low-cost housing have spawned neighborhoods -- and neighborhood schools -- that contrast sharply with that homogenous image.

Nowhere is the contrast more dramatic than at Groveton.

"We're increasingly confronted with . . . the same problems confronting inner city school districts," says Gerald Fill, the Fairfax School Board member who represents Groveton. "Groveton serves one of the most diverse neighborhoods in the school system."

At Groveton, which is just south of Alexandria, the county's richest youths share classes with some of its poorest. More than 20 percent of the school's 1,500 students are minorities. Students are drawn from neighborhoods of $250,000 homes along the Potomac River as well as trailer parks, cheap motels and federally subsidized apartment houses beside Rte. 1. Youths who can afford four years at Harvard University sit beside children of construction workers and welfare refugees from Alexandria's condominium conversions.

In one sense, Groveton is an educational ideal -- an American melting pot of urban and suburban, rich and poor, white, black and Asian. But the mix, some teachers and students acknowledge, is not always smooth.

"A collage of different types of groups brought together under one single roof presents a difficult problem," says Fill. "Sometimes the students . . . looking for an identity. . . get overzealous."

Groveton has its problems, but it still is no blackboard jungle. The band, the drama department and vocational programs at Groveton consistently win statewide honors. Every year, the school has a proportionate number of National Merit Scholarship winners. And the student diversity also offers a window into life outside the protection of suburbia.

"One of the advantages of attending Groveton High School is students get to interact with all kinds of students with all kinds of backgrounds," says Groveton Principal R. Don Ford.

On the surface, the recent incidents at Groveton appear to be racially motivated. But police, school officials, students and juvenile authorities say the conflict at Groveton is most one of social class: children of affluence, whether black or white, clashing with children of the less affluent and the poor.

"There's a lot of alienation here," says Groveton social studies teacher Lee Harris, who says the school gets blamed for problems that originate in the community it serves. "There's no money and the economy's bad. The kids feel it too. They're having trouble getting jobs."

The social and economic differences at Groveton create conflict. At best, it is playful: A student being teased for an Appalachian accent retaliates by mocking the alligator stitched on the shirt of his tormentor. Occasionally the interplay between the haves and have-nots becomes bitter.

"I don't know why we should expect behavior of the adolescent population to be a whole lot different than the adults," says Ruth Dell, who represented Groveton on the school board for six years. "The school is just a capsule of the humanity in the area."

Teachers, students and administrators complain that the recent events at Groveton present a distorted picture.

"I've taught in Fairfax County for 18 years and I don't believe I've ever had better students," says Susan Sunbury, a cosmetology teacher at Groveton. "You don't have to spend a lot of time telling them how important it is to have a skill. They all seem to know what the world of work means."

Yet, Groveton has its academic problems. It has the highest dropout rate in the county: 4.7 percent compared to the Fairfax average of 2.2 percent. Groveton ranks among the lowest schools in the county in standardized test scores. It also has the highest transiency rate. During the 1980-81 school year, 17 percent of the students either dropped out or transferred.

"The image of Groveton is a low-class school with a lot of 'grits'," complains Peter LaMarca, the senior class president. "Grits" is a pejorative term for poor, white students -- urban hicks, they also are called -- and the Groveton community is not fond of the tag.

"The school faculty has done an amazing job in years past blending these kids from such diverse economic and social groups," says Robert Weigl, a Groveton area psychologist who has worked with the juvenile court system there. "I don't think it's fair to go around asking why it won't work. The question is why isn't it working now?"

The diversity of the student body was a primary consideration in planning the current Groveton school which replaced an older, smaller high school in 1976. Community groups spent hundreds of hours studying school designs aimed at breaking down social class boundries.

Ironically, students at Groveton now say their school's design helps to promote cliques. The campus is made up of three buildings -- one housing shop and remedial courses, another fine arts courses such as photography, graphics and television and still another most academic courses.

"Having the three buildings sometimes makes people talk about people in a negative way," says Groveton senior Carolyn Neilan, the editor of the student newspaper, Tiger Rag. "People in one building are known as the artsy-craftsy type and in the academic building they are preppies and in the other building they're called grits."

More often than not, students say, these cliques transcend race: A middle-class white student living in Hollin Hills is more likely to hang out with a black middle-class student from neighboring Randall Estates than with a white from the lower income Nightingale Trailer Court on Rte. 1.

"The fight yesterday wasn't racially motivated; it was motivated over a drug ripoff," said Groveton Principal Ford, the day after about a dozen Fairfax County police cars responded to a distress call from an officer trying to break up a fight between 16-year-old girls on campus. "Had it not been for the incidents of the last few weekends, it would have been dropped right there."

Students and police say the trouble at Groveton really started more than a month ago at a McDonald's on the Rte. 1 strip that serves as a hangout for students from Groveton, Mount Vernon, Fort Hunt and Alexandria's T.C. Williams. School rivalries, some old feuds and a bit of racial tension turned a remark into an insult and the insult into a fight.

On Friday night, Oct. 23, about 40 youths gathered at opposite ends of a neon-lit McDonald's parking lot for a showdown. One group was mostly white and mostly Groveton students. The other group was black and reportedly made up of students from Fort Hunt, Mount Vernon and T.C. Williams, as well as a few nonstudents.

The two gangs were about 25 yards apart and closing when the door to a blue car opened and a shotgun was placed on its edge. One blast left 15 pellets in the chest and face of a Groveton student and scattered everyone else.

On the following Wednesday, said Ford, a black male student stole a bag of marijuana from a white female student. The next day, the male accused of stealing the marijuana was seen in a hall carrying a baseball bat. A white student intercepted the bat carrier and a fight involving four students followed.

As a result of that fight and earlier incidents at the school, Ford says he asked the Fairfax police to station one officer on campus for the rest of the day. Despite the officer's presence, the female student whose marijuana had allegedly been stolen the day before, pulled out a pair of nunchaks during the first lunch period and began fighting with a black female student.

While the officer attempted to put the girl in his patrol car, a crowd of 100 students formed a circle around the scene. A few students began taunting the officer, who grabbed his radio and called for backup.

"He was never in any danger," said Ford, who was in the circle of students. "He made it seem like there was a riot."

On Friday, students arrived at Groveton to find the campus patrolled by half a dozen Fairfax County school personnel, including two black administrators who had been called out of retirement for the special duty. Administrators said there was no major trouble that day, but rumors were in abundant supply.

"Everybody's coming to school packing nunchaks, pipes, guns . . . anything," said one Groveton junior the day after the arrests.

By week's end, five Groveton students had been arrested. Four were released to the custody of their parents and suspended for 10 days. A 17-year-old T.C. Williams student was arrested for firing the shotgun. Ford said the arrests would return Groveton's campus to a more characteristic calm.

"In the long run there is going to have to be more dialogue between students, parents and teachers," says Groveton PTA president Marcia Payne. "I think the kids have gotten over the incidents, but people in the community haven't."