This mystery element has a reputation for being tough. That's because when combined with other elements, it forms strong,

durable compounds. Some are nearly as hard as diamonds-the

hardest material on Earth. But in its pure form, the grayish-

white transition metal is soft enough to cut with a saw. Most

of the mystery element- about 75 percent-comes from

China. There are also large deposits in Canada, Russia, and the

U. S.

a is the answer to this question

explanation:

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.

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.