The Montgomery County school superintendent announced yesterday that the county's 102,356 students above the kindergarten level will be instructed in the dangers of marijuana and phencyclidine or PCP and that school officials will begin immediately to expel students charged with selling drugs.

Proclaiming new "initiatives" to deal with drugs use in the county schools, Superintendent Charles M. Bernardo said yesterday he was attempting to dispel any notion that Montgomery school officials were soft on drugs.

"The Post [in a story on a principal's reasons for not devoting more energy to policing school grounds for marijuana smoking] gave the impression that principals in the [Montgomery County public schools] were not of one mind on strict enforcement . . . of drug [violations]," he said.

"The principals share the view of parents of the seriousness of this problem," he said.

police have been raiding the grounds of high schools and junior highs in the county in an effort to curb drug use. Yesterday 11 more students were arrested, bringing the number arrests during the three-week crackdown to 117. Six of the youths arrested yesterday are students at Randolph Junior High School in Rockville, and five were arrested at Gaithersburg High School. One of the Gaithersburg students was also charged with distribution of marijuana.

Concern over drug use. Bernardo said, led him to draw up a list of "initiatives" to combat drug use in secondary schools.

Science teachers will have to discuss drugs and "emphasize the dangers of PCP and marijuana.

All teachers will be asked to speak about drugs in their classes and to be on the alert for students using drugs. Teachers who see students using marjuana will have to report them to the principal, who will report them to police.

Schools will have drug counseling groups for students "who may have drug abuse tendencies."

Administrators will visit classes and use the public address system to warn students that they will be arrested and suspended if found with drugs.

Student's who distribute drugs will be expelled.

Elementary school students will spend more time learning about the "dangers of drugs."

School hall monitors will receive training so that they more readily spot students using drugs.

Bernardo said use of marijuana by students "is an unfortunate consequence of the widespread public acceptance of pot." He said he believes the measures be announced to combat drug use will "reduce use of drugs on the school premises, but whethere it will reduce use of drugs by young people in their bedrooms and their cars is another question."

"This problem knows no bounds," he said. "There are those pressing for decriminalization of marijuana while we are pressing for greater enforcement of marijuana laws.

"Young people do hold different values than the main posture of the school system."

Bernardo denied that the number of students arrested by police during the past three weeks meant that school officials had been lax in enforcing marijuana laws. He said about half the arrests occurred off school grounds, where school officials have no authority. And during the 1977-78 school year, he said, school officials reported 470 students to police for using drugs.

But police spokesman Nancy Moses said the number of students reported to police last year by school officials - 470 - was relatively low. "That's not much when you arrest 100 in two weeks," she said. "In two months we could have had 400 arrests."

Bernardo said some of the measures he announced to curb drug use already have been in use at most schools, but that he wants all of the schools to use all of the measures.

We understand the need to insure consistency and completeness in the approaches used in each junior, middle, and senior high school," he said.