Formulas

• Every element has its own symbol (that is also a chemical formula!). Here we have the basic formulas. Note that they are always built up of one CAPITAL, often combined with one small letter.
  examples: Cu, H, Co, Ar
• Many elements can make simple ions, and those ions have simple ionic formulas.
  A couple of examples of that: Cu²⁺, Fe³⁺, I^- and Cl^- Behalve de eenvoudige, zijn er ook complexe ionen zoals bijvoorbeeld NH₄⁺, PO₄^3-,H₃O⁺, etcetera.
• the biggest part of the substances has a molecular formula; they show the real number of atoms of everyt element in such a molecule.
  examples: H₂O, C₂H₅OH.
• The electronic formula shows an atom or an ion or a molecule toghether with all its valency electrons (with dots or slashes), including the shared and non shared electrons.
• then there is the structural formula, that in fact equals the electronic formula without the shared electrons (electron pares)
• A formula that simply shows the proportion of the constituting elements, we call empiric formula.
  examples: NaCl, Cu, CaO, enz.
  The empiric formula is applied in the case of substances with ions and with metals.