Which of the following is true? a. lithium is the least reactive element in group 1, because it is the smallest and holds its valence electron more tightly than the others in the same group. b. cesium is the most active group 1 metal, because its valence electron is held more tightly than the others in the same group. c. group 1 elements are more reactive than the group 2 elements because they have more valence electrons to lose. d. the least reactive element in group 2 is the one with the largest atomic radium and the least amount of attraction between the nucleus

precipitation

explanation:

when it goes from cloud to rain/back to earth in the form of rain

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.