Each energy level contains a different number of sublevels which means each energy level can hold a different amount of electrons. how many electrons does the third energy level hold?
a. 18
b. 8
c. 2
d. 32

petroleum? coal maybe?

hey your not cool]      

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

it means there are 3 atoms of oxygen