(a) In an equilibrium reaction between gases Q and R, to form QR, the energy content of the reactants is 100 KJ and  that of the product is 54 kJ. The energy content of the activated complex is 210 KJ.

(i) Draw an energy profile diagram for the reaction. (ii) Determine the: I. activation energy of the reaction il. enthalpy change ΔH of the reaction. (iii) Write a balanced equation for the reaction. (iv) Give a reason for the answer given in 3(C)(iv). (iv) State whether the  reaction is exothermic or endothermic.

(b) Consider the following table:

Element	E	F	G	H
Atomic number	7	9	12	13

(i) Write the electron configuration for each of the elements. Element E, F, G, H 12 13 (ii) State: I. two elements that are metals; II. the elements(s) most likely to form an ion with a charge of +3; III. the element(s) which belong(s) to group VII. on the periodic table; IV. the formula of the compound formed between F and G. Atomic 

(c) Define the term isotopy  (d) Name the three building blocks of matter.