What kinds of evidence might be used to conclude that you have isolated a new element?

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Working with si (metric) units for each of the following commonly used measurements, indicate its symbol. liter gram milliliter kilogram meter centigram milligram centimeter kilometer second millimeter milliseconds

How many atoms of mg are present in 97.22 grams of mg? 6.022 × 1023 2.408 × 1024 4.818 × 1024 5.855 × 1025