9. Using clear labelled dot-cross diagrams explain how the following atoms bond together:
(i)
potassium and fluorine in potassium fluoride, (KF)
(ii)
hydrogen and oxygen in water, (H20)
(iii)
fluorine and boron in boron trifluoride, (BF3)

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.