Which element is not in the star that produced the “unknown spectrum”? How can you tell?

1) how many electrons are in each energy level of the following elements? a. he b. na c. na d. ne 2) how many valence electrons are percent in the following atoms? a. s b. mg c. be d. cl 3) which of the following elements are stable as atoms? a. he b. o c. cl d. ar if you are able to provide the work as to how you got the answers that would be greatly appreciated. : )

If 200.0g of copper(ll) sulfate react with an excess of zinc metal, what is the theoretical yield of copper

Draw the lewis dot structure for each of the following polyatomic ions