Atomic structure is very similar to the solar system, with the nucleus in the center and some negatively charged electrons surrounding it. The mass of the atom is almost entirely concentrated on the nucleus. The most accurate recap of this passage is:. ['The nucleus is at the center of the solar system.', 'The nucleus is composed of negatively charged protons and uncharged neutrons.', 'Atoms are composed of nuclei composed of electrons and positively charged protons and uncharged neutrons.', 'The nucleus is composed of extranuclear electrons, protons and neutrons.']