6. What group of elements is commonly used in jewelry and construction? a. Alkali Metals b. Halogens .c. Noble gases d. Transition metals
7. What family of elements are famous for being good disinfectants?

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ