Formulate a sample scientific hypothesis

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. : )

Abullet found at a crime scene may be used as evidence in a trial if the percentage of metals match to the composition of metals in a bullet from the suspect's ammunition. a forensic scientist's analysis of the bullet shows that it contains 11.9 g of lead, 0.5 g of tin, and 0.8 b of antimony. what is the percentage of lead metal in the bullet? express your answers to the one's place.

Can someone me with questions 12 and 13 plz.