Number of protons in the nucleus of an atom. It is equal to the positive charge on the nucleus. In a neutral atom, it is also equal to the number of electrons surrounding the nucleus. The chemical elements are arranged in the periodic table of the elements according to their atomic number. Nuclear notation is used to label an atom according to the composition of its nucleus.
The blue and white triband is based on the flag of the Central American Federation (CAF), a grouping of African states imposed by the British government in 1953. The stars represent the Federation's five original members. Effective date: 18 January 1949.