The periodic table of elements.
One of the most fundamental driving forces of chemical reactions is the electronic bonds that form between atoms. Electrons are negatively charged particles that orbit around the nucleus of a layered atom. Each electron shell of an atom has a certain number of electrons that it retains when possible, even if it unbalances the net charge of the atom; Electrons and protons individually have the same amount of electrical charge. The amount of charge a given atom has is expressed as a superscript to the right of the element name; for example, Na 1+ . The superscript number and sign is known as the billing number.
Electrons are negatively charged particles that orbit around the nucleus of an atom.
The outer electron shell of an atom is called the valence shell and is the basis for chemical reactions. Each shell has a variable number of electrons: the innermost shell contains two electrons, the next contains eight, and subsequent ones contain 18. The charge number comes from the natural tendency of atoms to have a full valence shell, either involve gain or loss of electrons. Elements are organized on the periodic table into groups based on the number of electrons in their valence shells. If two elements are in the same column or group on the periodic table, they have the same number of electrons available for chemical reactions.
Chlorine gains an electron and sodium loses an electron when they react with each other.
With the exception of hydrogen, the elements on the left side of the table (groups I and II) are alkali metals and alkaline earth metals. They have virtually empty valence shells, with only one or two electrons, respectively. Groups III to VII are non-metallic. Group III has three electrons, group IV has 4, and so on. Noble gases like neon, radon, and xenon have full valence shells and therefore do not react with other elements.
The charge number determines what type of charge an individual atom will have if it gains or loses electrons during an ionic chemical reaction. For example, sodium loses an electron when it reacts with chlorine; chlorine gains an electron. Their respective charges are 1+ and 1-. In their natural state, all elements have a zero charge number because there is no gain or loss of electrons.
Transition elements in columns 3 through 12 of the periodic table can be linked to different elements. Therefore, your billing numbers will vary. Group IV elements, like carbon, have a charge number of 4+/4-. They tend to form covalent bonds with other atoms, in which electrons are shared rather than transferred.