Antonio F. Azeredo da Silveira Jr., son of the Brazilian ambassador to the United States, was arrested Monday night and charged with shooting the bouncer of a Northwest Washington bar, but the charge was dismissed yesterday because the man has diplomatic immunity, according to law enforcement sources.

Silveira, who refused to give police his name or address at the time of his arrest, was initially listed as John Doe and charged with assault with a dangerous weapon. The charges were formally dropped in D.C. Superior Court yesterday after Silveira identified himself at the D.C. police central cell block Tuesday night, sources said.

According to a D.C. Police affidavit filed in court, Silveira pulled two pistols in The Godfather nightclub at 4934 Wisconsin Ave. NW, and was chased out of the establishment by the bouncer, Kenneth W. Skeen, and one other person. After a short chase, Silveira allegedly shot Skeen three times, before being subdued.

Skeen, 23, of Silver Spring, was listed in satisfactory condition at Georgetown University Hospital yesterday. He declined to be interviewed, but he was described by a visitor as being upset that the charges against Silveira were dropped.

Silveira, a student at American University, could not be reached for comment.

The staff at the Brazilian embassy was said to be stunned upon learning of the incident yesterday, according to an official there. The ambassador, Antonio F. Azeredo da Silveira, who had left for Brazil Sunday night to prepare for the arrival there of President Reagan, was informed by telephone yesterday, according to the official.

The ambassador "was quite shaken," the official said.

Reagan is on a four-nation tour of South America that began with a visit to Brazil Tuesday.

Helder Moraes, counselor and chief of the Embassy of Brazil's press section, last night released the following statement:

"The Brazilian ambassador's son was having a beer at a Wisconsin Avenue bar on the evening of November 29 when, for some trival matter connected with a pack of cigarettes, he was ordered by a bartender to leave the premises.

"He argued that he wanted to finish his beer, but in view of the threatening attitude of the bartender, he stepped back, stumbled and fell down, at which time he was kicked in the mouth.

"He then attempted to leave," Moraes said, "but was followed by five or six people who began to attack him, hitting him with a stone, striking him with sticks. Not being able to withstand the aggression any longer, he pulled a gun and, though laying down, fired some shots at random. He then lost consciousness and only came to at the police station."

According to the D.C. Police affidavit filed in court, Silveira got involved in an argument with the manager of the nightclub around 11 p.m. Monday, and pulled two pistols when the manager, who was not named, tried to escort him out.

"I'm with the Mafia and I'm going to kill you," Silveira said to the manager, according to a sworn affidavit filed in court by the investigating officer, James P. Vines.

"The defendant then pulled the trigger of the 6.35 [mm] Beretta, but it misfired," Vines said in the affidavit.

Silveira then ran out of the club, fired twice at his two pursuers, and was caught by them in front of 4911 43rd St. NW, where he fired three more shots, hitting Skeen in the hand, leg and abdomen, Vines said.

In a struggle that followed, Silveira was struck with an iron pipe, Vines said in his affidavit.

Silveira was taken to the 2nd District police headquarters, 3320 Idaho Ave. NW, where he refused to give his name, police said yesterday. He was formally booked as a "John Doe" and was then taken to D.C. General Hospital, where he was treated for a cut mouth, according to police and a hospital nurse.

Silveira identified himself as "Sanchez" at the hospital, according to a nurse there. On Tuesday D.C. Superior Court Hearing commissioner Evelyn Crawford Queen placed a $2,000 bond on a man by then listed on a police complaint as "Frank Sanchez."

Silveira, still refusing to reveal his identity, was discharged from D.C. General about 8 p.m. Tuesday night and taken to the central cell block at police headquarters, 300 Indiana Ave. NW, to await a court appearance scheduled yesterday.

While at the cell block, Silveira identified himself, police said. A Brazilian diplomat arrived a short time later and told officials that Silveira was the ambassador's son and thus was covered by diplomatic immunity, and he was released at around 10 p.m.

His name was blacked out on the police arrest book yesterday morning, police said.