Here is a look at the new Congress of People's Deputies that Soviets will elect Sunday:

COMPOSITIONThe Congress will have 2,250 members, elected in three different blocs of 750 members:

- Deputies chosen from the Communist Party, its affiliates, trade unions and professional and social organizations have been elected during the past two weeks. President Mikhail S. Gorbachev was chosen as one of 100 deputies representing the Communist Party.

- Voters will elect deputies from geographical districts of equal population throughout the country.

- Deputies will be elected representing the 15 constituent Soviet republics and autonomous territories and regions that are official homelands of more than 100 ethnic groups.

CAMPAIGN AND BALLOTING

In most districts, the elections are the first multicandidate races in memory. Campaigning began Dec. 26. Meetings of at least 500 people were empowered to nominate candidates, and the nominees were placed before an electoral commission that decided which candidates would go on the ballot.

Candidates were allowed up to 10 people on their campaign staff and permitted to campaign in the state-run media.

DUTIES OF THE CONGRESS

The congress will meet once a year. Once it is constituted, its duties will include:

- Electing the Soviet president, who will assume more power. The president will be in charge of general administration of the country and will lead the Defense Council, make proposals to the Supreme Soviet, negotiate with foreign countries and sign treaties and laws.

- Electing about 400 of its members to the country's actual working legislature, the Supreme Soviet, which will meet for two four-month terms each year.

- Making changes in the Soviet Constitution.

- Reviewing the president's choices for premier and the chairman of the Supreme Court.