Atom Introduction
Atoms are the smallest particles inseparable from chemical reactions. A positive atom contains a dense nucleus and a number of negatively charged electrons surrounding the nucleus. The nucleus of a negative atom is negatively charged, and the surrounding negative electrons are positively charged. The nucleus of a positive atom consists of positively charged protons and neutral neutrons. The anti-protons in the nucleus of a negative atom are negatively charged, thereby negatively charging the nucleus of a negative atom. When the number of protons is the same as the number of electrons, the atom is electrically neutral; otherwise, it is an ion with a positive or negative charge. Depending on the number of protons and neutrons, the type of atom is different: the number of protons determines which element the atom belongs to, and the number of neutrons determines which isotope of the element the atom is. Atoms make up molecules, and the same kinds of charges repel each other, and different kinds of charges attract each other.