What elements has a complete outermost energy level and is found in the 4th period

Given sno2 + 2h2 - sn + 2h20 tin oxide reacts with hydrogen to produce tin and water. how many moles of sno2 are needed to produce 500.0 grams of sn?

Over the last 90 years, scientists have added to the body of evidence supporting the big bang theory. what is the latest piece of evidence discovered in 2014?

Ted and emily played a mixed doubles tennis match against jack and brenda. in the second match. ted and brenda played against jack and emily. which type of chemical reaction does the situation demonstrate?