A covalent bond is formed between two non-metals that have similar electronegativities.
An <em>i</em><em>o</em><em>n</em><em>i</em><em>c</em><em> </em><em>b</em><em>o</em><em>n</em><em>d</em> is formed between a metal and a non-metal. Non-metals(-ve ion) are "stronger" than the metal(+ve ion) and can get electrons very easily from the metal. These two opposite ions attract each other and form the ionic bond.
Well if you go to Quiz-let it gives the answer the mass of a mole of compound is determined by adding the atomic masses of the atoms making up the molecules
Chlorine gas reacts to potassium bromide to form potassium chloride in solution and liquid bromine.
I hope this helps/answers your question! I vaguely remember getting this question before too