An atom can be an ion. But an ion cannot be an atom. An atom is the basic unit of an element that consist of proton, electrons and neutrons. Protons and neutron are located at the nucleus. Electrons are not located in the nucleus but rather outside of the nucleus. A proton is positively charge of +1. A neutron has a charge of 0. An electron has a negative charge of -1. The amount of protons in the atom is the atomic number which is arrange in the periodic table of elements. To determine the identity of an atom look at the number of positively charge proton in the atom’s nucleus. A stable atom has to have the same amount of protons and electrons and have no net charge. An ion is a particle or a group of particles that has a negative or positive charge. An ion is formed when an atom or group of atoms gain or lose electrons. Ions lose or gains electrons to be like a noble gas which has a complete valence shell. Electron configuration describes the arrangement of around the nucleus of an atom. It predicts the how atom will chemically bond and how it will behave. To find the electron configuration you first must find the atomic number of an element. The atomic number of an element is found on top of the element on the periodic table of elements. Next determined the charge of the atom. Uncharged atoms will have the same electron as shown in the periodic table. Charged atoms will have the more or less electrons based on what their charge is. Add or subtract depending if it has gain or loss an electron. Next determine which orbital set it is in. If it is s then it can hold 2 electron. P orbital can hold 6 electrons. The d orbital can hold 10. And the f orbital can hold 14. Next understand the electron configuration notation. 1s22s22p6 is a simple electron configuration notation. This shows that there are 2 electrons in the 1s orbital set, two electrons in the 2s orbital set and 6 electron in the 2p set. 2+2+6=10.