Which electron configuration represents the electrons in an atom of calcium in an excited state?
A)2-8-8
B)2-8-8-2
C)2-7-8-1
D)2-7-8-3

Ibeg i need 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?

Which of the following would be an accurate picture of the earth during the summer time of the northern hemisphere?

Suppose the universe were completely empty except for one object-a solid sphere moving through space of 100 km/s. what sort of path would the object be moving in? explain your answer