In what circumstances do scientists use observational research and opinion based research?

The circumstances when scientists use observational research and opinion based research is when they include animals or things that cannot control for a product. Observational research is a type of research which only observes ongoing behavior and studies about it and the results only rely on the behavior observed.

No table found. the question asks for covalent bond based on electronegativies

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer