Mixing chemical bonds

Until now we spoke about simple ions.
But after treating the main bonds in chemistry (ionic, metalic and covalent), you can understand that there are particles that contain combinations of those bonds.
therefore we look at the so called 'complex ion'.
In complex ions some atoms are connected via covalent bonds.
As a whole they do not make (in this case) a neutral molecule, but an ion with a positive or negative charge.
We know thar in all ions, simple and complex ones, the total number of protons (positive) and the total number of electrons (negarive) are not equal.

simple: Na+     Cl-     H+
complex: H3O+     OH     CO32-

If you know the charge of an ion, you can directly see how the distribution is of protons and electrons in that ion.
An ion with a 2- charge has two electrons more than protons.
The same for simple and for complex ions.

Complex ions mostly consist of two or more atoms of non metals; they stay toghether within that negative ion through covalent bondd. Sometimes metal atoms participate in a complex ion)

Most complex ions contain oxygen + another non metal, and they are connected via covalent bonds.

If in a substance no metal is present, then you mostly may conclude that this substance has no ions and that the substance is built up of neutral molecules.
All atoms in such a substance are connected via covalent bonds. An exeption is: salts of ammonia.

An example of a substance with different bond types is calciumcarbonate, CaCO3.
It is built up of three elements, the metal Calcium and the two non metals Carbon and Oxygen.
The metal Ca will probably be a positive ion, and the rest (CO32-) must be negative.
Between the ions is an ionic bond, but within the negative ion exist covalent bonds between O and C.