Bonds are determined by appearance, solubility in water, melting point and conductivity(in all three states of matter).
Ionic Bond: a bond formed between a metal and a nonmetal
Happens when an a metal loses an electron (becomes a cation) to a nonmetal with an incomplete outer shell.
-powdery/granular appearance, soluble in water, high melting point, only conducts electricity in liquid state and when dissolved in water
Covalent Bond: a bond that is usually formed between two nonmetals
Happens when atoms "share electrons".
-powdery/granular appearance, yes/no solubility, low melting point, does not conduct electricity at all
Metallic Bond: a bond formed between two metals
Happens when atoms literally "share all electrons making the electrons free to move about
-shiny, not soluble, high melting point, always conductive