The formulas mgo and co look very similar. what is the name for each compound? why do we name them differently?

MgO = magnesium oxide

CO = Carbon monoxide

Explanation:

MgO is ionic compound.

Ionic bond:

It is the bond which is formed by the transfer of electron from one atom to the atom of another element.  

Both bonded atoms have very large electronegativity difference. The atom with large electronegativity value accept the electron from other with smaller value of electronegativity.

The name of MgO is magnesium oxide. It is formed by the one magnesium atom and one oxygen atom. The oxidation state of magnesium is +2 and oxygen is -2. The  magnesium atom loses its two electrons and oxygen atom accept its two electrons.

Covalent bond:

It is formed by the sharing of electron pair between bonded atoms.  

The atom with larger electronegativity attract the electron pair more towards it self and becomes partial negative while the other atom becomes partial positive.

The name of CO is carbon monoxide. it is formed by the carbon and oxygen atoms. One atom of oxygen combine with one atom of carbon. The oxidation state of oxygen is -2 and carbon is +2. it is covalent compound having triple bond. The electron pairs are shared between carbon and oxygen atoms.