The electronegativity values of br, cl, f, h, mg,  and  na are given below. the bond between which two elements would be  primarily covalent? a. na and cl b. mg and f c. h and cl d. na and br

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?