What preliminary work is not necessary to complete before performing amass stoichiometric problem?

With the largest atoms and the smallest number of valence electrons and with the smallest atoms and the greatest number of valence electrons are the most reactive. a. nonmetals; metals b. nonmetals; transition elements c. transition elements; metals d. metals; nonmetals

How many moles are in 7.2 x 10^23 carbon molecules?

True or false exosphere is the least dense