What is the electron configuration of selenium

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

If the same amount of cacl2 is added to equal volumes of water and maple syrup, which will have the higher temperature?

Which of the following pairs of elements belong to the same groupa. h and he b. li and bec. c and pb d. ga and ge