Geologists have found Earth’s history is marked by several major events. What does the fossil record show took place around the same time Pangaea formed?A. single-celled organisms evolvedB. explosion of new life formsC. mass extinctionD. first animals lived on land

the role of the microscope world in creating new materials .

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

fe 55.85 g/mol and h2o 18.02 g/mol.