How can you tell if the molecule is ionic or covalent?Does an ionic compound HAVE to have a metal? and if the molecule has a metal does it HAVE to...

In nature there are no 100% ionic compounds. Each chemical
compounds has a certain percentage of ionic character in its bonds and the remaining
percentage as covalent bonds. The only compounds that are accepted as being 100%
covalent are the chemical combinations that happen between two similar atoms, like for
example the C-C bond existent in diamond, or the O-O bond in O2. Usually if atoms are
different in the compound it will present a certain percentage of ionicity in its bond,
the highest the difference between electronegativity of elements the highest the
percentage of existent ionic bonds. Thus usually the compounds like NaCl (first element
from group IA, last element from group VIIA) are regarded as ideal ionic compounds,
whereas compounds like GaAs, or InSb (first element from group IIIA, last element from
group VA) are regarded as covalent compounds (although they present about 10-15%
ionicity in their bonds). For metaloids, like Ge-Ge and Si-Si bonds, because they
contain atoms of the same type the bond is almost 100% covalent.