Help pls chemistry in the HMH

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

What prefix multiplier is appropriate for reporting a measurement of 5.57 ×10−5 m?

Ms. sullivan's class is designing a miniature roller coaster. after first setting it up, they find that it didn't have enough speed to go through the loop de loop. instead of taking out the loop, they decide to increase the height of the first hill the coaster goes down, and this adds the speed needed to make it through the loop. what would be a drawback to this plan in real life? a) no one likes loop de loops. b) there is no downside to this plan. c) a higher hill means a scarier ride. d) a higher hill takes more time and material to build.