UN Charter, Chapter II, Articles 3-6 concern Membership in the UN. Only states can be members of the United Nations.
Membership in different organs of the UN varies.
Membership of the principal organs is determined by the Charter of the United Nations and the Statute of the International Court of Justice:
In accordance with the Charter, the General Assembly (Article 22), Security Council (Article 29) and the Economic and Social Council (Article 68) may establish subsidiary organs.The decision to establish a subsidiary organ (also called the mandate) usually includes:
Websites, research guides, and FAQs with more information.
Chapter IV : Articles 9-22 : General Assembly
Chapter V : Articles 23-32 : The Security Council
Chapter VI : Articles 33-38 : Pacific Settlement of Disputes
Chapter VII : Articles 39-51: Action with Respect to Threats to the Peace, Breaches of the Peace, and Acts of Aggression
Chapter VIII : Articles 52-54 : Regional Arrangements
Chapter X : Economic and Social Council : Articles 61-72
Charter of the United Nations
Statute of the International Court of Justice
The International Court of Justice was established by the UN Charter. The Statute of the International Court of Justice is annexed to the Charter and is an integral part of the UN Charter. According to the ICJ website, the main purpose of the Statute is to organize the composition and functioning of the Court.
Chapter XI : Articles 73-74 : Declaration Regarding Non-Self-Governing Territories
Chapter XII : Articles 75-85 : International Trusteeship System
Chapter XIII : Articles 86-91 : The Trusteeship Council
Chapter III : Organs : Article 7
Chapter XV : The Secretariat : Articles 97-101
The Charter of the United Nations has the following parts: